Mooney 201. Fresh IRAN from G and N due to cam spalling.

No takeoffs yet due to engine quitting when the throttle is slowly pulled back from full Power to idle. Idle FF 2 gallons/hr. Engine can be made made to keep running by aggressively leaning when throttle is retarded. Difficult to keep running for a few seconds even with leaning. Owner afraid to fly due to problem says Captain obvious.

Suggestions?

My factory overall did have the exact same problem in fact it died on the roll out after the first flight landing.. That motivated us to get to the root of the problem.. Took the mixture link apart on the RH side of the throttle body, and screwed it in 1.5 turns to make it shorter, then reassembled it. this allowed us to adjust the mixture with the thumb wheel at idle lean enough to run well. Per Prevision service information letter S I L –RS67 you can have zero RPM rise at idle and that's where ours is happiest. One thing also to check after that is the intake to gasket flange at the head they are thin paper gaskets and on our engine all four were leaking.... if you install them wet with permatex aviation Sealer, they will not

Byron,

Great post. All plausible ideas.

What did shortening mixture arm accomplish. Richer or leaner?

Leaner. It was so rich it would flood and stall the engine. The thumb wheel didn't have enough adjustment.

Sounds like the servo is "sticking". Worth a try adjusting the mixture link since it is the easiest and least expensive avenue. I wouldn't try to fly it that way!

Charlie,

Thank you. Got word from friend fuel servo was sent in. G and N found the problem. No details yet.

Turns out fuel servo had a bent arm. Wonder how that happened. Can you say oops,I dropped it. Let us put it back on engine now.