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Re: UL: Re: gravity feed fuel

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  • Dana Hague
    ... Well, I have had no problems with the pump (to date). The previous owner had a forced landing, though (on his first solo in the airplane, first solo in
    Message 1 of 23 , Dec 1, 2009
      At 02:08 AM 12/1/2009, mark47620 wrote:
       
      First, let me ask, what problems do a rectangular pump and a pulse line have ?

      None that I can think of but I can think of a lot of ways to screw what I consider a really good and working sysytem up.

      Well, I have had no problems with the pump (to date).  The previous owner had a forced landing, though (on his first solo in the airplane, first solo in _any_ airplane!) when the fuel pump failed... it was a brand new pump.  Fortunately it cost him no more than a broken landing gear leg.  It's just one more potential point of failure.

      My thought was that if I'm moving the tank to above the engine anyway, why not simplify the system?  The UltraStar is unusual in that it's one of the few ultralights where you _can_ put the tank directly above the engine, such that you could do gravity feed with no significant effect from pitch changes.

      Fortunately it's a simple thing to try (on the ground!) and if I have any problems I can always put the pump back on.

      -Dana

      --
       Never vote for a politician who has to borrow a gun to go duck hunting
    • Dennis
      Dana Mine came with the fuel pump and the fuel tank above the engine. It worked fine. BUT it was hard to fill the tank with the wings and the gap seal in
      Message 2 of 23 , Dec 1, 2009
        Dana
        Mine came with the fuel pump and the fuel tank above the engine. It worked fine. BUT it was hard to fill the tank with the wings and the gap seal in place. Could not use another can to fill it. I needed a pump. I ended up putting a 5 gal cylindrical aluminum tank under the seat frame and using the pump. I just tilt the seat and fill it with a can. Best location I could come up with and if you do spill any fuel it doesn't go on the engine or wing. Both styles of my set up are in the Ultrastar Yahoo pictures. If you are worried about the fuel pump put on two of them in parallel with check valves. Then you would have some redundency.
        Dennis
      • daleandee
        I m not here to defend Zerkle. While it is pretty rare ... there are cases where this is true. Mark, you even stated this on the UL list a couple of years ago.
        Message 3 of 23 , Dec 1, 2009
          I'm not here to defend Zerkle. While it is pretty rare ... there are
          cases where this is true. Mark, you even stated this on the UL list a
          couple of years ago.

          Most people assume that higher EGTs always mean a leaner mixture but for
          every rule there are exceptions.

          Dale

          --- In FLY-UL@yahoogroups.com, "mark47620" <mark@...> wrote:

          > Zerkle thinks EGTs go up with richer mixtures so I wouldn't place a
          > lot of credence in his opinions. <SNIP>
        • Dana Hague
          Fueling isn t an issue now that I m using a pressurized fuel can to fill it. I m not worrying about the pump so much as wanting to make things simpler...
          Message 4 of 23 , Dec 1, 2009
            Fueling isn't an issue now that I'm using a pressurized fuel can to fill it.  I'm not worrying about the pump so much as wanting to make things simpler... which two pumps wouldn't be.

            I may yet just go with a seat tank and keep the pump.

            -Dana

            At 10:39 AM 12/1/2009, Dennis wrote:
             
            Mine came with the fuel pump and the fuel tank above the engine. It worked fine. BUT it was hard to fill the tank with the wings and the gap seal in place. Could not use another can to fill it. I needed a pump. I ended up putting a 5 gal cylindrical aluminum tank under the seat frame and using the pump. I just tilt the seat and fill it with a can. Best location I could come up with and if you do spill any fuel it doesn't go on the engine or wing. Both styles of my set up are in the Ultrastar Yahoo pictures. If you are worried about the fuel pump put on two of them in parallel with check valves. Then you would have some redundency.

            --
             I intend to live forever or die trying.
          • mark47620
            ... He wrote this in an article that appeared in the USUA magazine. Several folks noted he was wrong and some time later, he wrote another piece trying to say
            Message 5 of 23 , Dec 1, 2009
              --- In FLY-UL@yahoogroups.com, "daleandee" <daleandee@...> wrote:
              >
              >
              >
              > I'm not here to defend Zerkle. While it is pretty rare ... there are
              > cases where this is true. Mark, you even stated this on the UL list a
              > couple of years ago.
              >
              > Most people assume that higher EGTs always mean a leaner mixture but for
              > every rule there are exceptions.
              >
              > Dale

              He wrote this in an article that appeared in the USUA magazine.

              Several folks noted he was wrong and some time later, he wrote another piece trying to say why he was correct that even more confusing than the first,

              Sorry,,,,,,,,,,,

              mark
            • flybellaire2004
              Dana, Several factors can make your engine quit.. even a partially fouled plug. While the head pressures would in theory remain the same, how will you add a
              Message 6 of 23 , Dec 1, 2009
                Dana,
                Several factors can make your engine quit.. even a partially fouled plug. While the head pressures would in theory remain the same, how will you add a shut off valve without a lot more tubing? A fuel leak above your engine is not a good thought.

                The pumps are fairly reliable if you maintain them, and keep the pulse line short, and secured well. The filter should be after the pump. And if you feel more comfortable, add a good quality primer bulb near your seat. It can be used to keep a engine running.

                Jerry



                --- In FLY-UL@yahoogroups.com, Dana Hague <d-m-hague@...> wrote:
                >
                > Does anybody have any experience with gravity feed fuel systems on a
                > Cuyuna? I believe it was Mark Smith that related issues on the very early
                > Quicksilvers being gravity feed and not having adequate flow in a nose down
                > attitude... but the tank, if I'm not mistaken, was well forward of the engine.
                >
                > My Kolb currently has the stock fuel tanks forward of the seat with the
                > rectangular Mikuni pump feeding the VM32 carburetor. It works fine, but
                > for a couple of reasons I want to change to a single tank mounted above the
                > engine. With the tank above the engine I could go to gravity feed and
                > eliminate the fuel pump as a potential point of failure. I find no
                > information, though, on how high the fuel level must be above the
                > carburetor to insure adequate flow (I know I would need a larger float
                > needle, which is available). Having the tank directly above the engine
                > rather than forward as on the Quicksilver would eliminate any significant
                > change due to pitch attitude.
                >
                > In asking around, Roger Zerkle of ZDE gave me dire warnings about how it
                > was a bad idea, that the float level would change with changes in fuel head
                > pressure. There's some truth to that; I did some calculations and
                > determined that a 12" change in fuel level in the tank would mean a .04"
                > change in float level, which is just about the tolerance (±.04) given in
                > the manual for float arm height... but the fuel pressure varies in a pump
                > system, too, and motorcycles using the same carburetor seem to get by just
                > fine with gravity feed. I don't know how much an .04" float level change
                > would affect the mixture.
                >
                > -Dana
                > --
                > There are no bugs in this software, only unfulfilled features.
                >
              • Dana Hague
                Well, unless you mean a shutoff valve I can reach from the seat, it s no more difficult to install than any other tank. As for a primer bulb, no... I had one,
                Message 7 of 23 , Dec 2, 2009
                  Well, unless you mean a shutoff valve I can reach from the seat, it's no more difficult to install than any other tank.  As for a primer bulb, no... I had one, it's one of the more unreliable things you can put on an engine.

                  As for the tank above the engine, has there ever been a documented issue of this being a problem?  It's a common topic of discussion on the PPG forums, where the tank is often directly above the engine.  Bottom line is nobody's ever had an inflight fire due to the tank location above the engine, while several have had fires after damaging low mounted tanks in a hard landing.

                  -Dana

                  At 11:27 PM 12/1/2009, flybellaire2004 wrote:
                   
                  Several factors can make your engine quit.. even a partially fouled plug. While the head pressures would in theory remain the same, how will you add a shut off valve without a lot more tubing? A fuel leak above your engine is not a good thought.

                  The pumps are fairly reliable if you maintain them, and keep the pulse line short, and secured well. The filter should be after the pump. And if you feel more comfortable, add a good quality primer bulb near your seat. It can be used to keep a engine running.

                  --
                   The difference between genius and stupidity is that genius has limits.
                • mark47620
                  ... filter before the pump and no primer bulb, just another piece to flake off or stick inside mark BTW, adding the primer bulb would add a huge amount of
                  Message 8 of 23 , Dec 2, 2009
                    --- In FLY-UL@yahoogroups.com, "flybellaire2004" <flybellaire2004@...> wrote:
                    >
                    > Dana,
                    > Several factors can make your engine quit.. even a partially fouled plug. While the head pressures would in theory remain the same, how will you add a shut off valve without a lot more tubing? A fuel leak above your engine is not a good thought.
                    >
                    > The pumps are fairly reliable if you maintain them, and keep the pulse line short, and secured well. The filter should be after the pump. And if you feel more comfortable, add a good quality primer bulb near your seat. It can be used to keep a engine running.
                    >
                    > Jerry

                    filter before the pump and no primer bulb, just another piece to flake off or stick inside

                    mark



                    BTW, adding the primer bulb would add a huge amount of tubing to the system
                    >
                    >
                    >
                    > --- In FLY-UL@yahoogroups.com, Dana Hague <d-m-hague@> wrote:
                    > >
                    > > Does anybody have any experience with gravity feed fuel systems on a
                    > > Cuyuna? I believe it was Mark Smith that related issues on the very early
                    > > Quicksilvers being gravity feed and not having adequate flow in a nose down
                    > > attitude... but the tank, if I'm not mistaken, was well forward of the engine.
                    > >
                    > > My Kolb currently has the stock fuel tanks forward of the seat with the
                    > > rectangular Mikuni pump feeding the VM32 carburetor. It works fine, but
                    > > for a couple of reasons I want to change to a single tank mounted above the
                    > > engine. With the tank above the engine I could go to gravity feed and
                    > > eliminate the fuel pump as a potential point of failure. I find no
                    > > information, though, on how high the fuel level must be above the
                    > > carburetor to insure adequate flow (I know I would need a larger float
                    > > needle, which is available). Having the tank directly above the engine
                    > > rather than forward as on the Quicksilver would eliminate any significant
                    > > change due to pitch attitude.
                    > >
                    > > In asking around, Roger Zerkle of ZDE gave me dire warnings about how it
                    > > was a bad idea, that the float level would change with changes in fuel head
                    > > pressure. There's some truth to that; I did some calculations and
                    > > determined that a 12" change in fuel level in the tank would mean a .04"
                    > > change in float level, which is just about the tolerance (±.04) given in
                    > > the manual for float arm height... but the fuel pressure varies in a pump
                    > > system, too, and motorcycles using the same carburetor seem to get by just
                    > > fine with gravity feed. I don't know how much an .04" float level change
                    > > would affect the mixture.
                    > >
                    > > -Dana
                    > > --
                    > > There are no bugs in this software, only unfulfilled features.
                    > >
                    >
                  • Bill Holmes
                    The filter should be BEFORE the pump not after. -- Bill Holmes SP PPCL Light Sport Repairman - Maintenance (AP, WSC, PPC) Independent ROTAX Repair Facility
                    Message 9 of 23 , Dec 2, 2009
                      The filter should be BEFORE the pump not after.

                      --
                      Bill Holmes SP PPCL
                      Light Sport Repairman - Maintenance (AP, WSC, PPC)
                      Independent ROTAX Repair Facility
                      Born To Fly & Just Plane Stuff
                      Huber Air Park (E70)
                      2475 Rudeloff Rd.
                      Hangar 1B
                      Seguin TX. 78155
                      210-831-7123 ph.
                      208-279-0283 fax
                      Billholmes@...
                      http://www.born-2-fly.com
                      http://www.just-plane-stuff.com
                      http://www.lightsportaviationservice.com
                    • daleandee
                      Mark, Don t be sorry. If you don t understand it that s OK. You had spoken to it before but either you didn t understand it then or now you re all about
                      Message 10 of 23 , Dec 2, 2009
                        Mark,

                        Don't be sorry. If you don't understand it that's OK. You had spoken to
                        it before but either you didn't understand it then or now you're all
                        about "change." 8~)

                        Dale

                        --- In FLY-UL@yahoogroups.com, "mark47620" <mark@...> wrote:

                        > He wrote this in an article that appeared in the USUA magazine.

                        > Several folks noted he was wrong and some time later, he wrote another
                        > piece trying to say why he was correct that even more confusing than
                        > the first,

                        > Sorry,,,,,,,,,,,

                        > mark
                      • Bob Johnson
                        Hello Dana, OK I can t take it any more, why re-invent the wheel. I ve been flying UL s since 83, never had a fuel pump fail in 26 years. I rebuild-replace
                        Message 11 of 23 , Dec 2, 2009
                          Hello Dana,
                          OK I can't take it any more, why re-invent the wheel. I've been flying UL's since 83, never had a fuel pump fail in 26 years. I rebuild-replace every season, install a good fuel filter in FRONT of the pump, keep the lines short and mount the pump on vibration isolators. If you put the fuel tank on top and run it through a fuel pump it will still gravity feed through the pump barring that a valve or port isn't plugged (fuel filter in front). A good, clean, well installed pump system should keep you flying for years.
                          Bob

                          --- On Mon, 11/30/09, Dana Hague <d-m-hague@...> wrote:

                          From: Dana Hague <d-m-hague@...>
                          Subject: UL: gravity feed fuel
                          To: fLY-UL@yahoogroups.com
                          Date: Monday, November 30, 2009, 12:02 PM

                           
                          Does anybody have any experience with gravity feed fuel systems on a
                          Cuyuna? I believe it was Mark Smith that related issues on the very early
                          Quicksilvers being gravity feed and not having adequate flow in a nose down
                          attitude... but the tank, if I'm not mistaken, was well forward of the engine.

                          My Kolb currently has the stock fuel tanks forward of the seat with the
                          rectangular Mikuni pump feeding the VM32 carburetor. It works fine, but
                          for a couple of reasons I want to change to a single tank mounted above the
                          engine. With the tank above the engine I could go to gravity feed and
                          eliminate the fuel pump as a potential point of failure. I find no
                          information, though, on how high the fuel level must be above the
                          carburetor to insure adequate flow (I know I would need a larger float
                          needle, which is available). Having the tank directly above the engine
                          rather than forward as on the Quicksilver would eliminate any significant
                          change due to pitch attitude.

                          In asking around, Roger Zerkle of ZDE gave me dire warnings about how it
                          was a bad idea, that the float level would change with changes in fuel head
                          pressure. There's some truth to that; I did some calculations and
                          determined that a 12" change in fuel level in the tank would mean a .04"
                          change in float level, which is just about the tolerance (±.04) given in
                          the manual for float arm height... but the fuel pressure varies in a pump
                          system, too, and motorcycles using the same carburetor seem to get by just
                          fine with gravity feed. I don't know how much an .04" float level change
                          would affect the mixture.

                          -Dana
                          --
                          There are no bugs in this software, only unfulfilled features.


                        • Dana Hague
                          ... I ve never had a fuel pump failure either, but they do fail. As I said in an earlier message, the previous owner of my plane did have a forced landing
                          Message 12 of 23 , Dec 2, 2009
                            At 06:04 PM 12/2/2009, Bob Johnson wrote:
                             
                            OK I can't take it any more, why re-invent the wheel. I've been flying UL's since 83, never had a fuel pump fail in 26 years. I rebuild-replace every season, install a good fuel filter in FRONT of the pump, keep the lines short and mount the pump on vibration isolators. If you put the fuel tank on top and run it through a fuel pump it will still gravity feed through the pump barring that a valve or port isn't plugged (fuel filter in front). A good, clean, well installed pump system should keep you flying for years.

                            I've never had a fuel pump failure either, but they do fail.  As I said in an earlier message, the previous owner of my plane did have a forced landing when the brand new pump failed on the first flight.  Part of my job is doing FMEA (failure modes and effects analysis), and eliminating any potential point of failure, or reducing its effects, is a good thing.

                            A carburetor with a float needle sized for pump pressure will not feed enough fuel from gravity alone. 

                            There are not many ultralights whose geometry makes it possible to install a reliable gravity feed system, which is why it's almost never done.  Nor am I necessarily going to do it myself... but I do intend to move the tank, so I'm exploring it as an option.

                            -Dana

                            --
                             Ethernet (n): something used to catch the etherbunny
                          • Jeff Erekson
                            Bob - just to clarify - what is in front of the pump? The line between the pump and the carb? Or the line between the pump and the fuel tank? ... From: Bob
                            Message 13 of 23 , Dec 2, 2009
                              
                              Bob - just to clarify - what is "in front" of the pump? The line between the pump and the carb? Or the line between the pump and the fuel tank?
                               
                               
                              ----- Original Message -----
                              Sent: Wednesday, December 02, 2009 5:04 PM
                              Subject: Re: UL: gravity feed fuel

                              Hello Dana,
                              OK I can't take it any more, why re-invent the wheel. I've been flying UL's since 83, never had a fuel pump fail in 26 years. I rebuild-replace every season, install a good fuel filter in FRONT of the pump, keep the lines short and mount the pump on vibration isolators. If you put the fuel tank on top and run it through a fuel pump it will still gravity feed through the pump barring that a valve or port isn't plugged (fuel filter in front). A good, clean, well installed pump system should keep you flying for years.
                              Bob

                              --- On Mon, 11/30/09, Dana Hague <d-m-hague@...> wrote:

                              From: Dana Hague <d-m-hague@...>
                              Subject: UL: gravity feed fuel
                              To: fLY-UL@yahoogroups.com
                              Date: Monday, November 30, 2009, 12:02 PM

                               
                              Does anybody have any experience with gravity feed fuel systems on a
                              Cuyuna? I believe it was Mark Smith that related issues on the very early
                              Quicksilvers being gravity feed and not having adequate flow in a nose down
                              attitude... but the tank, if I'm not mistaken, was well forward of the engine.

                              My Kolb currently has the stock fuel tanks forward of the seat with the
                              rectangular Mikuni pump feeding the VM32 carburetor. It works fine, but
                              for a couple of reasons I want to change to a single tank mounted above the
                              engine. With the tank above the engine I could go to gravity feed and
                              eliminate the fuel pump as a potential point of failure. I find no
                              information, though, on how high the fuel level must be above the
                              carburetor to insure adequate flow (I know I would need a larger float
                              needle, which is available). Having the tank directly above the engine
                              rather than forward as on the Quicksilver would eliminate any significant
                              change due to pitch attitude.

                              In asking around, Roger Zerkle of ZDE gave me dire warnings about how it
                              was a bad idea, that the float level would change with changes in fuel head
                              pressure. There's some truth to that; I did some calculations and
                              determined that a 12" change in fuel level in the tank would mean a .04"
                              change in float level, which is just about the tolerance (±.04) given in
                              the manual for float arm height... but the fuel pressure varies in a pump
                              system, too, and motorcycles using the same carburetor seem to get by just
                              fine with gravity feed. I don't know how much an .04" float level change
                              would affect the mixture.

                              -Dana
                              --
                              There are no bugs in this software, only unfulfilled features.


                              GIF89aŒ
                            • mark47620
                              ... I think the rest of the list has it figured oyt, even if you don t,,,,,, BTW, I move tanks too as gravity feeds are better than sucking fuel up four feet
                              Message 14 of 23 , Dec 3, 2009
                                --- In FLY-UL@yahoogroups.com, Dana Hague <d-m-hague@...> wrote:
                                >
                                > At 06:04 PM 12/2/2009, Bob Johnson wrote:
                                > >
                                > >OK I can't take it any more, why re-invent the wheel. I've been flying
                                > >UL's since 83, never had a fuel pump fail in 26 years. I rebuild-replace
                                > >every season, install a good fuel filter in FRONT of the pump, keep the
                                > >lines short and mount the pump on vibration isolators. If you put the fuel
                                > >tank on top and run it through a fuel pump it will still gravity feed
                                > >through the pump barring that a valve or port isn't plugged (fuel filter
                                > >in front). A good, clean, well installed pump system should keep you
                                > >flying for years.
                                >
                                > I've never had a fuel pump failure either, but they do fail. As I said in
                                > an earlier message, the previous owner of my plane did have a forced
                                > landing when the brand new pump failed on the first flight. Part of my job
                                > is doing FMEA (failure modes and effects analysis), and eliminating any
                                > potential point of failure, or reducing its effects, is a good thing.
                                >
                                > A carburetor with a float needle sized for pump pressure will not feed
                                > enough fuel from gravity alone.
                                >
                                > There are not many ultralights whose geometry makes it possible to install
                                > a reliable gravity feed system, which is why it's almost never done. Nor
                                > am I necessarily going to do it myself... but I do intend to move the tank,
                                > so I'm exploring it as an option.
                                >
                                > -Dana


                                I think the rest of the list has it figured oyt, even if you don't,,,,,,

                                BTW, I move tanks too as gravity feeds are better than sucking fuel up four feet from a behind the seat tank.

                                My GT 400 originally comes with a tank behind the seat. It now has an overhead tank. My Hawk came with a behind the seat tank and it now has an overhead tank.

                                Overhead is better but both still have a pump !!

                                I have had 13 forced landings in one morning from a 'bad' fuel pump. Problem was solved when I grabbed a piece of trash pump from the garbage and installed it. Owner had done his own pump rebuild, a single Mikuni, and mis aligned the three parts, then tightened the bolts and punched some 'new' alignment holes in the new parts.

                                I changed out the newly repunched parts for more new parts and replaced it on the plane. And I might add for your benefit, that it had a gravity flow tank, a QS WS E model, and the engine ran fine until the bowl ran dry. The WS would get me up a hundred feet before quitting. I could 'save' it by cutting the throttle to save a restart too. Bowl was always full when checked,,,,,,,,,,and so on,,,,,,,,,,

                                Let us know how your experiment turns out. Many would like to eliminate all that weight of the pump.

                                mark
                              • ROGER MILLS
                                Tank, filter, pump, carb, in that order. Pump should get only filtered fuel. To: FLY-UL@yahoogroups.com From: jeff@xmsupplier.com Date: Wed, 2 Dec 2009
                                Message 15 of 23 , Dec 3, 2009
                                  Tank, filter, pump, carb, in that order.  Pump should get only filtered fuel.
                                   

                                  To: FLY-UL@yahoogroups.com
                                  From: jeff@...
                                  Date: Wed, 2 Dec 2009 23:23:35 -0600
                                  Subject: Re: UL: gravity feed fuel

                                   
                                  
                                  Bob - just to clarify - what is "in front" of the pump? The line between the pump and the carb? Or the line between the pump and the fuel tank?
                                   
                                   
                                  ----- Original Message -----
                                  Sent: Wednesday, December 02, 2009 5:04 PM
                                  Subject: Re: UL: gravity feed fuel

                                  Hello Dana,
                                  OK I can't take it any more, why re-invent the wheel. I've been flying UL's since 83, never had a fuel pump fail in 26 years. I rebuild-replace every season, install a good fuel filter in FRONT of the pump, keep the lines short and mount the pump on vibration isolators. If you put the fuel tank on top and run it through a fuel pump it will still gravity feed through the pump barring that a valve or port isn't plugged (fuel filter in front). A good, clean, well installed pump system should keep you flying for years.
                                  Bob

                                  --- On Mon, 11/30/09, Dana Hague <d-m-hague@comcast. net> wrote:

                                  From: Dana Hague <d-m-hague@comcast. net>
                                  Subject: UL: gravity feed fuel
                                  To: fLY-UL@yahoogroups. com
                                  Date: Monday, November 30, 2009, 12:02 PM

                                   
                                  Does anybody have any experience with gravity feed fuel systems on a
                                  Cuyuna? I believe it was Mark Smith that related issues on the very early
                                  Quicksilvers being gravity feed and not having adequate flow in a nose down
                                  attitude... but the tank, if I'm not mistaken, was well forward of the engine.

                                  My Kolb currently has the stock fuel tanks forward of the seat with the
                                  rectangular Mikuni pump feeding the VM32 carburetor. It works fine, but
                                  for a couple of reasons I want to change to a single tank mounted above the
                                  engine. With the tank above the engine I could go to gravity feed and
                                  eliminate the fuel pump as a potential point of failure. I find no
                                  information, though, on how high the fuel level must be above the
                                  carburetor to insure adequate flow (I know I would need a larger float
                                  needle, which is available). Having the tank directly above the engine
                                  rather than forward as on the Quicksilver would eliminate any significant
                                  change due to pitch attitude.

                                  In asking around, Roger Zerkle of ZDE gave me dire warnings about how it
                                  was a bad idea, that the float level would change with changes in fuel head
                                  pressure. There's some truth to that; I did some calculations and
                                  determined that a 12" change in fuel level in the tank would mean a .04"
                                  change in float level, which is just about the tolerance (±.04) given in
                                  the manual for float arm height... but the fuel pressure varies in a pump
                                  system, too, and motorcycles using the same carburetor seem to get by just
                                  fine with gravity feed. I don't know how much an .04" float level change
                                  would affect the mixture.

                                  -Dana
                                  --
                                  There are no bugs in this software, only unfulfilled features.


                                  GIF89aŒ


                                • ron ohler
                                  HI, Been flying over 20 years. The mikuni pump is a good unit. Simple as pie to rebuild. Worst fuel related problem I ever had was the result of a bulb primer
                                  Message 16 of 23 , Dec 3, 2009
                                    HI,
                                    Been flying over 20 years. The mikuni pump is a good unit. Simple as pie to rebuild. Worst fuel related problem I ever had was the result of a bulb primer who's valves became too hard for the pump to push fuel through. I was comming home from a 3 hour trip. Engine suddenly went lean and died. I was able to catch it and pump the squeeze bulb to get it to keep running. Kept it running for 15 miles to a small private strip. Spent a few hours cleaning the carb several times. I keep a pump rebuild kit on the plane and used it to rebuild the pump - and redid it several times. I finally tried removing the bulb and then it would run without quitting. With a pucker in my butt I flew it on home without the bulb. Once safely home I did what others (friends) had told me to do already. I used two tee's to put a bypass line around it's replacement.
                                    Best
                                    Ron O
                                  • mark47620
                                    ... Better to eliminate it altogetehr,, the tees won t keep internal crap from the pump from plugging stuff downstream of the primer bulb and bypass,,,,,, just
                                    Message 17 of 23 , Dec 3, 2009
                                      --- In FLY-UL@yahoogroups.com, ron ohler <ohler_ron@...> wrote:
                                      >
                                      > HI,
                                      > Been flying over 20 years. The mikuni pump is a good unit. Simple as pie to rebuild. Worst fuel related problem I ever had was the result of a bulb primer who's valves became too hard for the pump to push fuel through. I was comming home from a 3 hour trip. Engine suddenly went lean and died. I was able to catch it and pump the squeeze bulb to get it to keep running. Kept it running for 15 miles to a small private strip. Spent a few hours cleaning the carb several times. I keep a pump rebuild kit on the plane and used it to rebuild the pump - and redid it several times. I finally tried removing the bulb and then it would run without quitting. With a pucker in my butt I flew it on home without the bulb. Once safely home I did what others (friends) had told me to do already. I used two tee's to put a bypass line around it's replacement.
                                      > Best
                                      > Ron O

                                      Better to eliminate it altogetehr,,

                                      the tees won't keep internal crap from the pump from plugging stuff downstream of the primer bulb and bypass,,,,,,

                                      just best to install a primer pump directly to the carb, a couple pumps and fuel is in the engine, not just the bowl,,,,,,,,,,,

                                      usually first pull starts or a lot lesscranking on the starter,,,,,

                                      mark
                                    • ron ohler
                                      Hi Mark, I know you like primers. I don t. I ve seen them fail too. The mikuni has an excellent enrichener. I have mine equipped with a remote cable actuator.
                                      Message 18 of 23 , Dec 3, 2009
                                        Hi Mark,
                                        I know you like primers. I don't. I've seen them fail too. The mikuni has an excellent enrichener. I have mine equipped with a remote cable actuator. I've had them this way on my Pterodactyls(Cuyuna 430's and ULII-02), my Falcon Safety Craft and my Drifter. All could be started from the pilots seat. I've personally shown disbelievers that my Drifter's ULII-02 could be started on a cold (24 degrees) Michigan January day with 3 pulls after sitting nearly 2 months in an unheated hanger. That's fine with me. The starter rope was changed to a cable as it's routed over 2 pullies. There is still a lot of frictional loss that probably reduces pull speed enough to add one pull to the starting procedure. If I was concerned with disintegration of parts from the bulb primer getting into the carb adding a simple secondary fuel filter before the carb would suffice.
                                        Best regards,
                                        Ron

                                        --- On Thu, 12/3/09, mark47620 <mark@...> wrote:

                                        > From: mark47620 <mark@...>
                                        > Subject: Re: UL: gravity feed fuel
                                        > To: FLY-UL@yahoogroups.com
                                        > Date: Thursday, December 3, 2009, 9:53 PM
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                                        > --- In FLY-UL@yahoogroups.
                                        > com, ron ohler <ohler_ron@. ..> wrote:
                                        >
                                        > >
                                        >
                                        > > HI,
                                        >
                                        > > Been flying over 20 years. The mikuni pump is a good
                                        > unit. Simple as pie to rebuild. Worst fuel related problem I
                                        > ever had was the result of a bulb primer who's valves
                                        > became too hard for the pump to push fuel through. I was
                                        > comming home from a 3 hour trip. Engine suddenly went lean
                                        > and died. I was able to catch it and pump the squeeze bulb
                                        > to get it to keep running. Kept it running for 15 miles to a
                                        > small private strip. Spent a few hours cleaning the carb
                                        > several times. I keep a pump rebuild kit on the plane and
                                        > used it to rebuild the pump - and redid it several times. I
                                        > finally tried removing the bulb and then it would run
                                        > without quitting. With a pucker in my butt I flew it on home
                                        > without the bulb. Once safely home I did what others
                                        > (friends) had told me to do already. I used two tee's to
                                        > put a bypass line around it's replacement.
                                        >
                                        > > Best
                                        >
                                        > > Ron O
                                        >
                                        >
                                        >
                                        > Better to eliminate it altogetehr,,
                                        >
                                        >
                                        >
                                        > the tees won't keep internal crap from the pump from
                                        > plugging stuff downstream of the primer bulb and
                                        > bypass,,,,,,
                                        >
                                        >
                                        >
                                        > just best to install a primer pump directly to the carb, a
                                        > couple pumps and fuel is in the engine, not just the
                                        > bowl,,,,,,,, ,,,
                                        >
                                        >
                                        >
                                        > usually first pull starts or a lot lesscranking on the
                                        > starter,,,,,
                                        >
                                        >
                                        >
                                        > mark
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