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Engine basics => Engine set up tips => Topic started by: Larry Wong on April 11, 2008, 03:26:54 PM

Title: F P 35
Post by: Larry Wong on April 11, 2008, 03:26:54 PM

Question is what cause it to quit, when it starts a wing over?

Fuel is Sig 10% with Aero-1
Plug is Thunderbolt 4 stroke
Prop is Bill Lee 11x4 3 bld
Tank is uniflow-tryed with pressure/with out 
this is the same setup in the last plane and had no problems.

 HB~> HB~> HB~> HB~> HB~> HB~>

Title: Re: F P 35
Post by: phil c on April 11, 2008, 06:00:15 PM

Quits how?  Burp rich or does it die lean?

Uniflow tanks are notorious for quitting if they develop the tiniest leak in the wrong spot.  If you have a leak along the top, back edge, turning a hard inside corner will drop the fuel below the leak and suddenly the mixture changes radically and the motor quits.  Just depends on where the leak is.  After all, the uniflow vent is just a controlled leak down in the wedge near the pickup.

Title: Re: F P 35
Post by: Manuel Cortes on April 12, 2008, 01:21:14 AM

Hi all.
Mine began to do the same.......the P/S was worn, new P/S solved the problem...check it if it has a lot of work in it, just in case.
Regards.
Manuel

Title: Re: F P 35
Post by: Larry Wong on April 12, 2008, 02:20:04 PM

Thanks guys for the input, I'm thinking it's the P/C  It just quits like it was turn off not rich or lean, just stops, the oil from exhaust looks black also.

Title: Re: F P 35
Post by: john e. holliday on April 13, 2008, 07:36:27 AM

You didn't state if the compression was bad or not.  If the compression is good, did you try some fresh fuel?  You mention only the wingover as causing the engine to quit, is that the only maneuver?  To me an 11-4 three blade sounds like a lot of prop.  I run 11-5 two blades and sometimes a 11-4 depending on the weather.  In reality there are so many variables that could cause your problem.  I even had a fuel line that had a small split in it one time.  Anyway, let us know what you find.  DOC Holliday

Title: Re: F P 35
Post by: phil c on April 13, 2008, 08:28:18 AM

Yes, an 11/4 3 blade is a heck of a lot of prop for a 35.  A 9/4 3 blade would be about right.  The black is generally the piston blowing out the exhaust due to overheating, or else some other place where there is something rubbing that shouldn't be.

Title: Re: F P 35
Post by: Bob Hudak on May 01, 2008, 07:42:43 PM

Are you using a tongue muffler? My fp 35 on a tongue muffler quit in outside loops,I tried everything. What ended up fixing the problem was drilling the holes larger on the tongue muffler.Let em' breath!