91AC flameout
 

Hi Dave

I have a new 91AC (it has the woodrif key on the crankshaft) and I am having flameout problems with it. It has had less than one gallon of Wildcat 20/20 through it. I have it mounted sideways and I have a 14x10 APC prop on it. I'm getting around 8900rpm on the high end and 2000-2100 on the low end. The regulator is flush with the body.

So here's my problem. Whenever I go inverted or point the nose up, the engine flames out. It doesn't seem to speed up as if it were lean, it just dies. I checked the clunk in my tank and I am sure that's not the problem. I'm at a loss as to what the problem might be. Any ideas would be greatly appreciated.

Thanks
Chris

RE: 91AC flameout
 

Can you duplicate the problem on the ground?

RE: 91AC flameout
 

I tried with no luck to duplicate the problem on the ground. So I reset the regulator, LS, and HS adjustments and put a new glow plug in it. When I flew it yesterday, I didn't have the problem with flameout, but anytime the engine was in an inverted attitude during a manuever, the engine would bog down. There was a noticable loss of power and I could definitely hear the RPM drop. That happened on the ground as well as while airborne.

Any ideas?

RE: 91AC flameout
 

Reset both the valves to .003"
You may need to lean both the regulator and idle, but do the regulator first.

Let me know.

RE: 91AC flameout
 

Things are getting weird.

I checked the valve clearance and it was dead-on. I took it out yesterday and tried it. I swapped props to a Master Airscrew 15x8 and I can't get more than about 8200rpm. The engine keeps running however, but it seems to be lacking in power. So, I put back on the APC 14x10 and could get the top end close to 8800rpm. As soon as I picked up the plane and changed it's orientation, the engine quit. No surging, just died.

A couple of other notes. The engine was very hot after running, too hot to touch. After a run, I could hear an air leak coming from somewhere. And lastly, there seems to be a ton of oil on the engine and in the enginc compartment. I have the exhaust deflected so that this oil can't be from the muffler.

Any ideas?

RE: 91AC flameout
 

Sounds like something is loose. Time to pull the engine a check all the bolts. It has to be sucking air someplace.

RE: 91AC flameout
 

I took the engine out and checked all the bolts. Everything was tight, so I decided to change the gaskets. That seems to have solved the problem. The midrange is still a bit off and needs a bit of fine-tuning, but it's running stronger and I haven't had a dead-stick since I changed out the gaskets.

Thanks for all your help.

RE: 91AC flameout
 

Glad you found the problem. Keep us posted on your progress.

Good Flying!