engine stumbles

[bobp]

I have a cont 65 with Bendix mags, Stromberg carb. The carb was overhauled last Sept.

The engine has started to stumble, not at the same rpm, sometimes 1100, 1200 and 1400 rpms, and only when the engine is warm. I believe this was discussed sometime ago but I can"t find the thread. Any Ideas anyone can give me on this would be great, Thanks in advance, Bob

[fearofpavement]

Re: engine stumbles

First thing I would check is for intake leaks. carb tight to the mounting flange, hose clamps snug on the rubber intake hoses and so forth...

[magman]

Re: engine stumbles

My first action would be to see if it does it with Carb Heat ON.

If the problem goes away it means your IDLE MIXTURE is too Lean.

To correct it back out the Mixture Screw 1/2 turn & repeat the

run-up w/o Carb Heat.


If it's still doing it get a Leaf Blower or Shop vac.

Connect to Exhaust STack & seal w DuctTape.

Close Throttle.

Spray with soapy solution.

You can check both intake & exhaust systems this way.

[Ragwing nut]

Re: engine stumbles

how fast are you pushing the throttle foward? It will stuble if done to fast.