ETLB Squawk Forums — Archive

Had an engine out and forced landing yesterday.  And....it was my own fault.  

My 503 was idling great during the summer.  As the weather cooled, it started idling at  lower rpm, so I turned in the idle screw a little to keep it around 2000. That worked fine until yesterday evening.  I was south of town over farm fields, at around 1100 agl, looking for my flying buddies who had already landed at their friend's farm.  I spotted them about 1/2 mile away,  quickly pulled the power back to idle, and put the nose down quickly.  The engine started sputtering at very low idle(1000-1200rpm). I started feeding in throttle, and it died.  Oh joy.....

I pulled back to best glide, and tried a couple of re-starts.  It would crank and idle, but feeding in throttle, fast or slow, with/without choke, killed it.  At 500 agl I decided to forget restarting, and dead sticked it in, landing on the turn row near my buddies.  After sitting a minute, it cranked back up using choke on a warm engine and ran fine at 1/4 throttle or above.
My buddy Keith and I talked about it(he's a damn good 2-stroke mechanic), and we concluded that the idle mixture was just too lean for the cooler weather.  That, combined with my rapid throttle reduction, starved the engine.  Adjustments will be made, and the engine tested.

Guys,  if you fly in colder weather, check your engine's idle settings both cold and hot. And don't "snatch" throttle back without testing it thoroughly both on the ground, and while over your home airport.

Thanks, and glad everything went well.

When I get the EIS back from GRT I'll once again be flying a 4 stroke, but if the wx is cold I'll be sure to check the idle mixture.

Did you turn the idle screw or the low speed air screw? You maybe need to turn the air screw in just a little to richen up the low speed. Also if you are seeing higher exhaust temps you may need to go to a larger main jet if running hot at 3/4 throttle and above or raise your jet needle a notch if your midrange is hot and running lean. By doing those things you shouldn't have to change your idle/carb slide stop screw. Turning in you idle/slide stop screw will greatly reduce the effectiveness of your choke.

Tjspindler

TJ,

I adjusted the idle speed/stop screw.  The idle mixture screw will likely need enriching up a little, as the weather cools.

Update:  a few days ago,  I checked the idle air screw. Discovered that the screw was 1-1/2 turns out from bottom.  Bing carb  rep said to bottom out the screw, then back it out a 1/2 turn and check.  After testing a couple of times running the engine on the ground, I wound up settling on 5/8 - 3/4 turn out from bottom.  I warmed the engine,  took off, and tried to replicate my engine failure while in the airport traffic pattern. Throttle full open, then full closed rapidly.  Engine did just fine;  I think it's fixed.