Keith,

A lot of people are observing some changes recently. I'm wondering if your
engine is getting too hot. Is this the same prop as before, or a new prop. If
a new prop, then I would wonder about pitch. If the same prop, I would wonder
about the high temperatures and high humidity being a factor.

New place for fuel? Could you by chance now be having ethanol in your fuel and
previously didn't?

Beery

--- In ppgbiglist@yahoogroups.com, "keithbenitez" <keithbenitez@...> wrote:
>
> I am having a problem with my Blackdevil 172 engine. I turn it on and it runs
great for about 4 minutes or so, then slowly the RPMs drop. It starts off at a
nice powerful 7600RPM then it goes down to eventually 6600RPM. If I let it go
back to idle and then go back to full throttle I can get it to go to maybe
7400RPM but again it just continues to drop.
>
> Here is what I have done and checked so far.
> * Disassembled the carb and cleaned it all out.
> * Made sure there are no bubbles or air leaks in the fuel line.
> * Fuel lines are attached with zip ties that have been looped over twice to
make sure there is no pitch spot.
> * My prop is a GSC 48 ground adjustable pitch prop and I have adjusted the
pitch both lower and higher (also checked with a 45 ground adjustable).
> * Replaced the redrive belt to a new one (had the problem before the replace).
> * Checked the cylinder head O-ring and head nuts for proper torque.
> * Checked and even replaced the fuel clunk in the fuel tank.
> * Removed and checked the muffler for blockage.
> * Replaced the automatic decompressor with a new manual one.
>
> Please help, what am I missing?
>
> Keith
>