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RE: Re: Old Gas - A Seizure Demon

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  • Jay D
    Joe, I really doubt it was old gas related. My hangar mate let his plane sit 1.5 yrs while a divorce was finishing up. He then went out to the plane and
    Message 1 of 26 , Nov 1, 2003
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      Joe, I really doubt it was old gas related. My hangar mate let his plane
      sit 1.5 yrs while a divorce was finishing up. He then went out to the
      plane and started it up, checked it out and flew it to its new grass
      strip home. Then he topped the gas off and kept flying. He runs 93
      Ammco. While I had back surgery (twice) I let my gas sit for about 2
      months. It was 87 with Wal Mart oil. All I'm really saying is that the
      egt will show a hot seizure if that is what it was. If the gas looses
      octane it can pre-ignite causing spark knock like you hear in a car with
      low octane gas in a high test rated car when you accelerate up a hill.
      This is tough on the crank and will loose considerable power, but not
      make the piston seize, IMHO.

      Jay D

      -----Original Message-----
      From: Dave [mailto:daved@...]
      Sent: Friday, October 31, 2003 11:13 PM
      To: FLY-UL@yahoogroups.com
      Subject: UL: Re: Old Gas - A Seizure Demon

      Is it the same fuel in the tank from your last seizure ? I agree
      that it may not of been the old gas . I've gone with gas 2 mos old .
      A friend of mine will let his plane sit all winter, then spring go up
      with the gas in his tank . I dont agree with that but he's been doin'
      it for 20 some years with no problems . Did you notice the temps
      before it seized? Also what is the jetting ? Is it dual carb?
      Dave


      --- In FLY-UL@yahoogroups.com, "george_rf1" <george_rf1@y...> wrote:
      > I do not believe your seizure was caused by old gas , I think you
      are
      > on the wrong diagnosing path,
      >
      > George
      >
      > -----------------------------------------------------------
      >
      > --- In FLY-UL@yahoogroups.com, "Joe Griffey" <griffeyj@b...> wrote:
      > > Had a reality check yesterday. My 503 seizing after only 5 hrs
      > following overhaul (dunked in lake in July), became a sudden
      > awakening after looking at my pistons, down at Ronnie's. All the
      > tell-tell signs were there of old unstable fuel burn. For what
      it's
      > worth to those that have not paid attention (like me), don't let
      old
      > gas accumulate in your tank(s). Unconsciously, I have allowed far
      > too large a percentage of old gas to remain in my tanks while
      adding
      > to and topping off for short local flying. We all have been
      educated
      > in in topping off for each flight.....for safety purposes. That
      > doesn't work when you fly only 30 min's at a time. Why not?
      Simple
      > logic. Ya end up with too large a percentage of old gas in the
      tank
      > that is often several weeks old (if ya only fly once a week). I
      > learned that lesson the hard way.
      > >
      > > Joe G.
      > >
      > >
      > > [Non-text portions of this message have been removed]





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    • Planeman
      Joe I agree with George. With 5hrs on rebuild I would suspect the workmanship ,or the parts used. There are 10 s of thousands of 2 strokers in service and I
      Message 2 of 26 , Nov 1, 2003
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        Joe
        I agree with George.
        With 5hrs on rebuild I would suspect the workmanship ,or the parts used.
        There are 10's of thousands of 2 strokers in service and I bet many of them are
        fueled with gas mixtrue older than what you had . Heck my chain saws and weed
        wacker sits around with premix that is over a year old ,and have always been
        used seasonal.
        Dave R


        >
        > Great George! You disagree, but WHY? And WHAT is the RIGHT diagnosing
        > path, in you opinion? Joe G.
        >
        > ----- Original Message -----
        > From: "george_rf1" <george_rf1@...>
        > To: <FLY-UL@yahoogroups.com>
        > Sent: Friday, October 31, 2003 7:13 PM
        > Subject: UL: Re: Old Gas - A Seizure Demon
        >
        >
        > > I do not believe your seizure was caused by old gas , I think you are
        > > on the wrong diagnosing path,
        > >
        > > George
        > <snip>
        >
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      • jerb
        Does adding gas stabilizer like Sta-Bil help. I ve been adding it at the recommended rate when I mix up a batch. Comparing to before and after I began using
        Message 3 of 26 , Nov 1, 2003
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          Does adding gas stabilizer like Sta-Bil help. I've been adding it at the
          recommended rate when I mix up a batch. Comparing to before and after I
          began using it, it does seem like the engine runs better on old
          premix. Fuel in the planes tank appears to age faster than when stored in
          a sealed gas can. I contribute this to the fact that aircraft tank being
          vented to free air versus building a slight pressure as with a sealed
          storage can.
          jerb
        • Planeman
          Jerry Since I transport all my fuel in translucent carboy s ,I remember taking note of a warning I read long ago . It referenced letting fuel sit in the sun in
          Message 4 of 26 , Nov 1, 2003
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            Jerry
            Since I transport all my fuel in translucent carboy's ,I remember taking note
            of a warning I read long ago . It referenced letting fuel sit in the sun in
            translucent cans. Maybe the ultra violet light has something to do with aging.
            Just throwing that out to you .At any rate I keep my cans out of the sun all
            the time.
            Dave R


            >
            > Does adding gas stabilizer like Sta-Bil help. I've been adding it at the
            > recommended rate when I mix up a batch. Comparing to before and after I
            > began using it, it does seem like the engine runs better on old
            > premix. Fuel in the planes tank appears to age faster than when stored in
            > a sealed gas can. I contribute this to the fact that aircraft tank being
            > vented to free air versus building a slight pressure as with a sealed
            > storage can.
            > jerb
            >
            >
            >
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          • robert hensarling
            ... From: Jay D To: Sent: Saturday, November 01, 2003 5:08 AM Subject: UL: RE: Re: Old Gas - A Seizure
            Message 5 of 26 , Nov 1, 2003
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              ----- Original Message -----
              From: "Jay D" <jdewberry@...>
              To: <FLY-UL@yahoogroups.com>
              Sent: Saturday, November 01, 2003 5:08 AM
              Subject: UL: RE: Re: Old Gas - A Seizure Demon

              Hey Jay, email me off list about your back surgery. I'm fixing to go there
              (titanium rods and screws, can't wait!).
              Robert


              > Joe, I really doubt it was old gas related. My hangar mate let his plane
              > sit 1.5 yrs while a divorce was finishing up. He then went out to the
              > plane and started it up, checked it out and flew it to its new grass
              > strip home. Then he topped the gas off and kept flying. He runs 93
              > Ammco. While I had back surgery (twice) I let my gas sit for about 2
              > months. It was 87 with Wal Mart oil. All I'm really saying is that the
              > egt will show a hot seizure if that is what it was. If the gas looses
              > octane it can pre-ignite causing spark knock like you hear in a car with
              > low octane gas in a high test rated car when you accelerate up a hill.
              > This is tough on the crank and will loose considerable power, but not
              > make the piston seize, IMHO.
              >
              > Jay D
              >
              > -----Original Message-----
              > From: Dave [mailto:daved@...]
              > Sent: Friday, October 31, 2003 11:13 PM
              > To: FLY-UL@yahoogroups.com
              > Subject: UL: Re: Old Gas - A Seizure Demon
              >
              > Is it the same fuel in the tank from your last seizure ? I agree
              > that it may not of been the old gas . I've gone with gas 2 mos old .
              > A friend of mine will let his plane sit all winter, then spring go up
              > with the gas in his tank . I dont agree with that but he's been doin'
              > it for 20 some years with no problems . Did you notice the temps
              > before it seized? Also what is the jetting ? Is it dual carb?
              > Dave
              >
              >
              > --- In FLY-UL@yahoogroups.com, "george_rf1" <george_rf1@y...> wrote:
              > > I do not believe your seizure was caused by old gas , I think you
              > are
              > > on the wrong diagnosing path,
              > >
              > > George
              > >
              > > -----------------------------------------------------------
              > >
              > > --- In FLY-UL@yahoogroups.com, "Joe Griffey" <griffeyj@b...> wrote:
              > > > Had a reality check yesterday. My 503 seizing after only 5 hrs
              > > following overhaul (dunked in lake in July), became a sudden
              > > awakening after looking at my pistons, down at Ronnie's. All the
              > > tell-tell signs were there of old unstable fuel burn. For what
              > it's
              > > worth to those that have not paid attention (like me), don't let
              > old
              > > gas accumulate in your tank(s). Unconsciously, I have allowed far
              > > too large a percentage of old gas to remain in my tanks while
              > adding
              > > to and topping off for short local flying. We all have been
              > educated
              > > in in topping off for each flight.....for safety purposes. That
              > > doesn't work when you fly only 30 min's at a time. Why not?
              > Simple
              > > logic. Ya end up with too large a percentage of old gas in the
              > tank
              > > that is often several weeks old (if ya only fly once a week). I
              > > learned that lesson the hard way.
              > > >
              > > > Joe G.
              > > >
              > > >
              > > > [Non-text portions of this message have been removed]
              >
              >
              >
              >
              >
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              >
              >
              >
              >
              >
              >
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              >
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            • Ralph
              I just joined the list last night. I usually monitor the kolb-list and have been on that one for many years. There are times where a guy just can t seem to get
              Message 6 of 26 , Nov 1, 2003
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                I just joined the list last night. I usually monitor the kolb-list
                and have been on that one for many years. There are times where a guy
                just can't seem to get enough of UL flying. Know what I mean?

                Anyway, I believe it's very important to keep moisture out of the
                tank as much as possible. I cover the vent with duck tape when done
                flying, but have to make sure I remove it before flight. Ethanol in
                the gas will tend to absorb moisture and where there is moisture,
                there's no oil. I have flown with ethanol and without and don't see
                any differences. It's required by law to have it in the gasoline here
                in Minnesota. Sealed containers keep the moisture out and this keeps
                the fuel more usable in my opinion.

                One more thing: I have dedicated fuel containers for the plane and
                nothing else. Contamination is another problem and this helps reduce
                it.

                Ralph
                Original Firestar
                16 years flying it
              • Rick Pitcher
                ... 3 week old gas caused your 5 hour sine rebuilt engine to sieze? I doubt it. Mebbe you should ask for the next rebuild to be done under warranty? Rick P.
                Message 7 of 26 , Nov 1, 2003
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                  Joe Griffey wrote:
                  > Had a reality check yesterday. My 503 seizing after only 5 hrs following overhaul (dunked in lake in July), became a sudden awakening after looking at my pistons, down at Ronnie's. All the tell-tell signs were there of old unstable fuel burn. For what it's worth to those that have not paid attention (like me), don't let old gas accumulate in your tank(s). Unconsciously, I have allowed far too large a percentage of old gas to remain in my tanks while adding to and topping off for short local flying. We all have been educated in in topping off for each flight.....for safety purposes. That doesn't work when you fly only 30 min's at a time. Why not? Simple logic. Ya end up with too large a percentage of old gas in the tank that is often several weeks old (if ya only fly once a week). I learned that lesson the hard way.
                  >
                  > Joe G.

                  3 week old gas caused your 5 hour sine rebuilt engine to sieze? I doubt it.
                  Mebbe you should ask for the next rebuild to be done under warranty?

                  Rick P.
                • J Pridemore
                  ... From: Rick Pitcher ... I agree with Rick, and many others. If old gas was a problem I would have a seizure every time I fly. I
                  Message 8 of 26 , Nov 1, 2003
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                    ----- Original Message -----
                    From: Rick Pitcher <rick.pitcher@...>
                    > 3 week old gas caused your 5 hour sine rebuilt engine to sieze? I doubt it.
                    > Mebbe you should ask for the next rebuild to be done under warranty?>>>

                    I agree with Rick, and many others.
                    If old gas was a problem I would have a seizure every time I fly.
                    I have flown with gas left in the tank for several months during the winter,
                    and just topped it off afterward.
                    I have a 12 gallon tank, and top off everytime I fly even if I only 30
                    minutes, or 2 hours.
                    No problems, if I leave the plane sitting for 2-3 weeks, I just fly it when I
                    finally get to the airstrip.
                    I would look for a cause somewhere else.



                    Jerry Pridemore
                    Jerry@...

                    People are more violently opposed to fur than leather, because it's safer to
                    harass rich women, than motorcycle gangs.

                    Trikes Rule!!!
                    Pictures of my Trike, and Trike info at:
                    www.JerryPridemore.com
                  • pilot11ams
                    ... once......don t ... Joe, All I can tell you is from experience as I am not a chemical engineer, but utilizing Sta-Bil in premixed gasoline does not hurt
                    Message 9 of 26 , Nov 1, 2003
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                      "Joe Griffey" wrote:

                      > Andrew, there's an interesting input. I've heard more than
                      once......don't
                      > use additives in pre-mix for ROTAX engines????? Joe G.

                      Joe,

                      All I can tell you is from experience as I am not a chemical
                      engineer, but utilizing Sta-Bil in premixed gasoline does not hurt
                      it. It is very common here in Northern Minnesota to store seasonal
                      motors, two stroke or four stroke, with gasoline stabilized with Sta-
                      Bil. From snowmobiles and boats down to grass trimmers, we've been
                      doing it for 30 years and never had a problem. And as someone else
                      pointed out, here in Minnesota we have a lot of gasoline with
                      Ethanol in it which can attract moisture. To combat that problem, we
                      occassionally add a can of Sea Foam or other name brand carb cleaner
                      into the fuel to isolate and remove any water. Add in a seasonal
                      draining of the tank, usually spring and fall, and your water issues
                      will go away.

                      Sta-Bil is cheap, effective and it works.

                      Andrew

                      ----- Original Message -----
                      > From: "pilot11ams" <avslack@c...>
                      > To: <FLY-UL@yahoogroups.com>
                      > Sent: Friday, October 31, 2003 5:28 PM
                      > Subject: Re: UL: Old Gas - A Seizure Demon
                      >
                      >
                      > <snip>
                      > > I don't agree with some of the assumptions, but if there is a
                      > > concern with gas getting old, you may simply want to purchase a
                      > > bottle of gas stabilizer and squirt a little in when you fill up.
                      > >
                      > > Simple, cheap and effective.
                      > >
                      > > Andrew
                      > <snip>
                    • jerb
                      Mine tanks or cans are not in the sun except while flying and visiting, other wise the tanks/cans are in the hangar. The one question I have does the premixed
                      Message 10 of 26 , Nov 1, 2003
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                        Mine tanks or cans are not in the sun except while flying and visiting,
                        other wise the tanks/cans are in the hangar. The one question I have does
                        the premixed fuel age faster in a vented tank compared to a sealed gas can
                        where it can build up some pressure.
                        jerb

                        At 07:06 AM 11/1/03 -0500, you wrote:
                        >Jerry
                        >Since I transport all my fuel in translucent carboy's ,I remember taking note
                        >of a warning I read long ago . It referenced letting fuel sit in the sun in
                        >translucent cans. Maybe the ultra violet light has something to do with aging.
                        >Just throwing that out to you .At any rate I keep my cans out of the sun all
                        >the time.
                        > Dave R
                        >
                        >
                        > >
                        > > Does adding gas stabilizer like Sta-Bil help. I've been adding it at the
                        > > recommended rate when I mix up a batch. Comparing to before and after I
                        > > began using it, it does seem like the engine runs better on old
                        > > premix. Fuel in the planes tank appears to age faster than when stored in
                        > > a sealed gas can. I contribute this to the fact that aircraft tank being
                        > > vented to free air versus building a slight pressure as with a sealed
                        > > storage can.
                        > > jerb
                        > >
                        > >
                        > >
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                        > >
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                      • jerb
                        Joe G, Sorry to hear about this but I don t think anyone has asked these questions. With your experience I would think you have already covered this ground
                        Message 11 of 26 , Nov 2, 2003
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                          Joe G,
                          Sorry to hear about this but I don't think anyone has asked these
                          questions. With your experience I would think you have already covered
                          this ground but sometimes in our eagerness to fly we miss or short cut things.
                          * How many hours total time on the engine - before the rebuild -
                          looking for possible piston slop.
                          * After the rebuild did you do the Rotax breakin procedure?
                          * If you didn't do the break in, had you done a full power run up with
                          tail tied down to see what static RPM and EGT's were doing? (After an
                          engine has been disturbed, I fine this to be a good practice.)
                          * Were any pistons or rings changed?
                          * Did they replace the main seals - Mag, center, and PTO?
                          * How did the plugs look examining them immediately after the seizure?
                          * Did you do any changes to prop pitch?
                          * Was the in-line gas filter new or reused? (also if replaced did it
                          have adequate flow capacity - some don't).
                          * Do you have a squeeze-bulb? (they are know to leak air, add
                          contaminates, or for the check valve to stick causing fuel starvation)
                          * Have you rebuilt/replaced the fuel pump since the splash down event?
                          * Is your tank vent open (not partially plugged)?
                          The things that generally contribute to a seizure are generally cold engine
                          placed under high power demand, under pitched prop, some thing contributing
                          to cause a lean fuel mixture, lack of oil?

                          I run old gas but I generally try to dilute it with fresh 92 octane
                          especially if its over 2 weeks old. If I don't have much old fuel left and
                          I expect to run it out, I will use 87 octane. Without diluting I can say
                          it does appear old gas contributes to more carbon build up. One thing I
                          have noticed since I began using the Sta-Bil gas stabilizer, I can tell the
                          difference in how the engine runs with old gas. Old gas it would kind of
                          act like it was under a load like it lacked energy, using the Sta-Bil I
                          don't notice that. As result I have gone to the practice all fuel gets
                          stabilizer regardless.

                          Unless you have run only "really old" gas, I don't see where it directly
                          should have caused a seizure in that amount of time. Something else has
                          had to contributes to this - carbs, there settings, prop pitch, cold
                          engine, leak causing fuel leaning, weak fuel pump or pulse. You have used
                          proper thicker wall pulse tubing from the engine to the fuel pump.
                          jerb


                          At 03:27 PM 10/31/03 -0600, you wrote:
                          >Had a reality check yesterday. My 503 seizing after only 5 hrs following
                          >overhaul (dunked in lake in July), became a sudden awakening after looking
                          >at my pistons, down at Ronnie's. All the tell-tell signs were there of
                          >old unstable fuel burn. For what it's worth to those that have not paid
                          >attention (like me), don't let old gas accumulate in your
                          >tank(s). Unconsciously, I have allowed far too large a percentage of old
                          >gas to remain in my tanks while adding to and topping off for short local
                          >flying. We all have been educated in in topping off for each
                          >flight.....for safety purposes. That doesn't work when you fly only 30
                          >min's at a time. Why not? Simple logic. Ya end up with too large a
                          >percentage of old gas in the tank that is often several weeks old (if ya
                          >only fly once a week). I learned that lesson the hard way.
                          >
                          >Joe G.
                          >
                          >
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                        • Joe Griffey
                          jerb...I ve been there, done that on most of the things you listed, or since given those details in additional comments. Went through every detail with my
                          Message 12 of 26 , Nov 2, 2003
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                            jerb...I've "been there, done that" on most of the things you listed, or
                            since given those details in additional comments. Went through every detail
                            with my regional ROTAX Repair Center owner, etc., etc.. A couple of points
                            and questions that I've not mentioned before:

                            .......I had recently changed my prop pitch (was getting close to 6500 rpms
                            at FT). I'm setting the prop to reduce it back to around 6200, to work the
                            engine harder.

                            ........I do full runups every time I've had any parts replacement.

                            ........even when it seized, my plugs looked good.

                            ........after my ditch in the lake (July), I replaced fuel pump, filter,
                            lines and everything.

                            ........have question about: "proper thicker wall pulse tubing"? I use a
                            different tubing than fuel lines, but it is sufficient thickness to prevent
                            closer or any form of blockage.
                            Never heard this one before....what's the deal here?

                            ........I discarded my squeeze bulb over a year ago.

                            Joe G.




                            ----- Original Message -----
                            From: "jerb" <ulflyer@...>
                            To: <FLY-UL@yahoogroups.com>
                            Sent: Sunday, November 02, 2003 10:46 AM
                            Subject: Re: UL: Old Gas - A Seizure Demon


                            > Joe G,
                            > Sorry to hear about this but I don't think anyone has asked these
                            > questions. With your experience I would think you have already covered
                            > this ground but sometimes in our eagerness to fly we miss or short cut
                            things.
                            > * How many hours total time on the engine - before the rebuild -
                            > looking for possible piston slop.
                            > * After the rebuild did you do the Rotax breakin procedure?
                            > * If you didn't do the break in, had you done a full power run up with
                            > tail tied down to see what static RPM and EGT's were doing? (After an
                            > engine has been disturbed, I fine this to be a good practice.)
                            > * Were any pistons or rings changed?
                            > * Did they replace the main seals - Mag, center, and PTO?
                            > * How did the plugs look examining them immediately after the seizure?
                            > * Did you do any changes to prop pitch?
                            > * Was the in-line gas filter new or reused? (also if replaced did it
                            > have adequate flow capacity - some don't).
                            > * Do you have a squeeze-bulb? (they are know to leak air, add
                            > contaminates, or for the check valve to stick causing fuel starvation)
                            > * Have you rebuilt/replaced the fuel pump since the splash down event?
                            > * Is your tank vent open (not partially plugged)?
                            > The things that generally contribute to a seizure are generally cold
                            engine
                            > placed under high power demand, under pitched prop, some thing
                            contributing
                            > to cause a lean fuel mixture, lack of oil?
                            >
                            > I run old gas but I generally try to dilute it with fresh 92 octane
                            > especially if its over 2 weeks old. If I don't have much old fuel left and
                            > I expect to run it out, I will use 87 octane. Without diluting I can say
                            > it does appear old gas contributes to more carbon build up. One thing I
                            > have noticed since I began using the Sta-Bil gas stabilizer, I can tell
                            the
                            > difference in how the engine runs with old gas. Old gas it would kind of
                            > act like it was under a load like it lacked energy, using the Sta-Bil I
                            > don't notice that. As result I have gone to the practice all fuel gets
                            > stabilizer regardless.
                            >
                            > Unless you have run only "really old" gas, I don't see where it directly
                            > should have caused a seizure in that amount of time. Something else has
                            > had to contributes to this - carbs, there settings, prop pitch, cold
                            > engine, leak causing fuel leaning, weak fuel pump or pulse. You have used
                            > proper thicker wall pulse tubing from the engine to the fuel pump.
                            > jerb
                            <snip>
                          • charlie4_66043
                            ... 6500 rpms ... work the ... 6500 rpm at full throttle in level flight at top speed is correct. 6200 rpm at full throttle in a steep climb on takeoff is also
                            Message 13 of 26 , Nov 2, 2003
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                              --- In FLY-UL@yahoogroups.com, "Joe Griffey" <griffeyj@b...> wrote:
                              > .......I had recently changed my prop pitch (was getting close to
                              6500 rpms
                              > at FT). I'm setting the prop to reduce it back to around 6200, to
                              work the
                              > engine harder.
                              >

                              6500 rpm at full throttle in level flight at top speed is correct.

                              6200 rpm at full throttle in a steep climb on takeoff is also
                              correct.

                              Which did you mean?

                              Charlie
                            • jerb
                              Lockwood, CPS and the likes sell a clear tubing that is 1/4 ID but near 1/2 OD. It is a fuel/oil resistant tubing that has thicker walls to prevent from
                              Message 14 of 26 , Nov 2, 2003
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                                Lockwood, CPS and the likes sell a clear tubing that is 1/4" ID but near
                                1/2" OD. It is a fuel/oil resistant tubing that has thicker walls to
                                prevent from flexing with the pulses that operate the fuel pump. If you
                                use a soft or thin wall tubing it will give and reduce the strength of the
                                pulses to the fuel pump. Don't use fuel line for your pulse line as it is
                                known for the plies to separate and collapse inward under the vacuum result
                                in no or weak pulses. There are some fuel/oil resistant vacuum line that
                                probably OK if thicker walled so as not to yield.

                                Note, if you decreased the pitch of your prop too much where it not loading
                                the engine adequately it will force you to retard the throttle and put the
                                engine into a lean condition. It can seize very quickly and suddenly. Had
                                a novice fellow flyer decide to remove one blade from his prop. While he
                                twice increased the pitch and made runs down the runway he didn't do a full
                                RPM run static up with the tail tied down. On take off and climb out he
                                had to back off the throttle to prevent red lining the engine. The engine
                                suddenly seized just after turning downwind. Had he waited another half
                                hour the experienced guys returned from a morning flight and would of
                                helped him and prevented the incident. That ended his UL flying career as
                                his wife would not let him fly any UL's again.
                                jerb

                                At 12:57 PM 11/2/03 -0600, you wrote:
                                >jerb...I've "been there, done that" on most of the things you listed, or
                                >since given those details in additional comments. Went through every detail
                                >with my regional ROTAX Repair Center owner, etc., etc.. A couple of points
                                >and questions that I've not mentioned before:
                                >
                                >.......I had recently changed my prop pitch (was getting close to 6500 rpms
                                >at FT). I'm setting the prop to reduce it back to around 6200, to work the
                                >engine harder.
                                >
                                >........I do full runups every time I've had any parts replacement.
                                >
                                >........even when it seized, my plugs looked good.
                                >
                                >........after my ditch in the lake (July), I replaced fuel pump, filter,
                                >lines and everything.
                                >
                                >........have question about: "proper thicker wall pulse tubing"? I use a
                                >different tubing than fuel lines, but it is sufficient thickness to prevent
                                >closer or any form of blockage.
                                >Never heard this one before....what's the deal here?
                                >
                                >........I discarded my squeeze bulb over a year ago.
                                >
                                >Joe G.
                                >
                                >
                                >
                                >
                                >----- Original Message -----
                                >From: "jerb" <ulflyer@...>
                                >To: <FLY-UL@yahoogroups.com>
                                >Sent: Sunday, November 02, 2003 10:46 AM
                                >Subject: Re: UL: Old Gas - A Seizure Demon
                                >
                                >
                                > > Joe G,
                                > > Sorry to hear about this but I don't think anyone has asked these
                                > > questions. With your experience I would think you have already covered
                                > > this ground but sometimes in our eagerness to fly we miss or short cut
                                >things.
                                > > * How many hours total time on the engine - before the rebuild -
                                > > looking for possible piston slop.
                                > > * After the rebuild did you do the Rotax breakin procedure?
                                > > * If you didn't do the break in, had you done a full power run up with
                                > > tail tied down to see what static RPM and EGT's were doing? (After an
                                > > engine has been disturbed, I fine this to be a good practice.)
                                > > * Were any pistons or rings changed?
                                > > * Did they replace the main seals - Mag, center, and PTO?
                                > > * How did the plugs look examining them immediately after the seizure?
                                > > * Did you do any changes to prop pitch?
                                > > * Was the in-line gas filter new or reused? (also if replaced did it
                                > > have adequate flow capacity - some don't).
                                > > * Do you have a squeeze-bulb? (they are know to leak air, add
                                > > contaminates, or for the check valve to stick causing fuel starvation)
                                > > * Have you rebuilt/replaced the fuel pump since the splash down event?
                                > > * Is your tank vent open (not partially plugged)?
                                > > The things that generally contribute to a seizure are generally cold
                                >engine
                                > > placed under high power demand, under pitched prop, some thing
                                >contributing
                                > > to cause a lean fuel mixture, lack of oil?
                                > >
                                > > I run old gas but I generally try to dilute it with fresh 92 octane
                                > > especially if its over 2 weeks old. If I don't have much old fuel left and
                                > > I expect to run it out, I will use 87 octane. Without diluting I can say
                                > > it does appear old gas contributes to more carbon build up. One thing I
                                > > have noticed since I began using the Sta-Bil gas stabilizer, I can tell
                                >the
                                > > difference in how the engine runs with old gas. Old gas it would kind of
                                > > act like it was under a load like it lacked energy, using the Sta-Bil I
                                > > don't notice that. As result I have gone to the practice all fuel gets
                                > > stabilizer regardless.
                                > >
                                > > Unless you have run only "really old" gas, I don't see where it directly
                                > > should have caused a seizure in that amount of time. Something else has
                                > > had to contributes to this - carbs, there settings, prop pitch, cold
                                > > engine, leak causing fuel leaning, weak fuel pump or pulse. You have used
                                > > proper thicker wall pulse tubing from the engine to the fuel pump.
                                > > jerb
                                ><snip>
                                >
                                >
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                                [Non-text portions of this message have been removed]
                              • Joe Griffey
                                jerb.....I think you have something here. That is why I m adding bit to my prop. Don t think I was near redlining, but I suspect my engine was not loading
                                Message 15 of 26 , Nov 2, 2003
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                                  jerb.....I think you have something here. That is why I'm adding bit to my
                                  prop. Don't think I was near redlining, but I suspect my engine was not
                                  loading adequately.......a real possibility that would refocus my thinking
                                  (from bad gas). The pulse line tubing I'm using should be adequate (thicker
                                  than my fuel line). And, I would think, that any concern for fuel/oil in
                                  the pulse line would indicate greater problems with the fuel pump or
                                  engine??? Joe G.


                                  ----- Original Message -----
                                  From: "jerb" <ulflyer@...>
                                  To: <FLY-UL@yahoogroups.com>
                                  Sent: Sunday, November 02, 2003 5:42 PM
                                  Subject: Re: UL: Old Gas - A Seizure Demon


                                  > Lockwood, CPS and the likes sell a clear tubing that is 1/4" ID but near
                                  > 1/2" OD. It is a fuel/oil resistant tubing that has thicker walls to
                                  > prevent from flexing with the pulses that operate the fuel pump. If you
                                  > use a soft or thin wall tubing it will give and reduce the strength of the
                                  > pulses to the fuel pump. Don't use fuel line for your pulse line as it is
                                  > known for the plies to separate and collapse inward under the vacuum
                                  result
                                  > in no or weak pulses. There are some fuel/oil resistant vacuum line that
                                  > probably OK if thicker walled so as not to yield.
                                  >
                                  > Note, if you decreased the pitch of your prop too much where it not
                                  loading
                                  > the engine adequately it will force you to retard the throttle and put the
                                  > engine into a lean condition. It can seize very quickly and suddenly.
                                  Had
                                  > a novice fellow flyer decide to remove one blade from his prop. While he
                                  > twice increased the pitch and made runs down the runway he didn't do a
                                  full
                                  > RPM run static up with the tail tied down. On take off and climb out he
                                  > had to back off the throttle to prevent red lining the engine. The engine
                                  > suddenly seized just after turning downwind. Had he waited another half
                                  > hour the experienced guys returned from a morning flight and would of
                                  > helped him and prevented the incident. That ended his UL flying career as
                                  > his wife would not let him fly any UL's again.
                                  > jerb
                                  <snip>
                                • Joe Griffey
                                  On takeoff, Charlie :-( Joe G. ... From: charlie4_66043 To: Sent: Sunday, November 02, 2003 2:13
                                  Message 16 of 26 , Nov 2, 2003
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                                    On takeoff, Charlie :-( Joe G.

                                    ----- Original Message -----
                                    From: "charlie4_66043" <radfordc@...>
                                    To: <FLY-UL@yahoogroups.com>
                                    Sent: Sunday, November 02, 2003 2:13 PM
                                    Subject: Re: UL: Old Gas - A Seizure Demon


                                    > --- In FLY-UL@yahoogroups.com, "Joe Griffey" <griffeyj@b...> wrote:
                                    > > .......I had recently changed my prop pitch (was getting close to
                                    > 6500 rpms
                                    > > at FT). I'm setting the prop to reduce it back to around 6200, to
                                    > work the
                                    > > engine harder.
                                    > >
                                    >
                                    > 6500 rpm at full throttle in level flight at top speed is correct.
                                    >
                                    > 6200 rpm at full throttle in a steep climb on takeoff is also
                                    > correct.
                                    >
                                    > Which did you mean?
                                    >
                                    > Charlie
                                    <snip>
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