Engine ran rough for a few seconds after restart.

JOhnH

Touchdown! Greaser!
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This has only happened a couple of times, but now I am starting to worry.
This is a Continental IO 520B with GAMI injectors in a V35 Bonanza.

After refueling and restarting, the engine ran rough for a few seconds before smoothing out. While starting, after the engine caught, it "dieseled" (I know that is the wrong term, but that is what it sounded like). It seemed like maybe one or two cylinders were misfiring. Pumping the throttle for a few seconds seemed to keep it running till it smoothed out.

I kind of thought it might be a fouled plug because of the taxi to the fuel pump. But I am wondering if it could be a stuck valve or something else.
 
Probably no big deal. They hate to be started at the hangar, moved to the pumps, shut down, and then re-started while just luke warm.

Pumping the throttle will do nothing good.......it is fuel injected.

Fix the throttle where, from experience, it will idle at 1200RPM.

After start, bump the boost pump occasionally to keep it running.............it shouldn't take too much of that, or something is wrong.
 
Don't overthink it - systems are pretty simple.

Note that, when you restart with engine warm, pretty good chance there are a few slugs of vapor in the lines that might have a cylinder or three stumbling until it's all worked through...
 
As gruber said, the -520 is fuel injected, don't pump the throttle, but instead, flicker the boost pump on and off. I doubt it was a sticking valve since that would typically last a bit longer than what you described while having a "ticking" sound associated with it, before gradually smoothing out.

Might not hurt to have a mechanic take a peek if this persists.
 
The aircraft fuel injection systems are a bit less sophisticated than what you may be used to in your automobile - particularly when it comes to hot restarts.
My CFI taught me to rub the fuel servo with a chicken bone before a hot start - usually you have to tape it to a stick and reach in from the cowl outlets to reach.
 
It starts faster if you pitch the airplane to the optimal angle of attack.
 
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