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Petedfl12

Member
During my run up - noticed the engine (O-320 H2AD)was rough passing 1300-1400 RPM. Did the mag check at 1700 (checked good) then returned back to 1300-1400 slowly and again rpm was erratic + rough. RPM dropping up and down between 1100 - 1400 . Checked each mag at that range ( 1300-1400 ) and the engine behaved the same. Ran the engine lean , full rich - still the same.All other RPM range is normal with normal mag check ( RPM drop of 150 ) not rough or erratic - only see this behavior between 1300-1400 RPM.
Any thoughts as to what may be causing this. All thoughts and comments are welcome.

Thanks Pete
RV6-A
 
Petedfl12 said:
All other RPM range is normal with normal mag check ( RPM drop of 150 ) not rough or erratic - only see this behavior between 1300-1400 RPM.
Any thoughts as to what may be causing this. All thoughts and comments are welcome.
Click to expand...

Running rough, or just a bit of a hesitation or dead spot as you advance the throttle? There's a transition from idle jet to power jet in the carburetor somewhere near there.

- mark
 
What happens at about 1400 Rpm is - the RPM drop back to 1100 then back up to 1300-1400 by it self. With that said the engine is rough as it cycles up and down in that range. Hesitates to get past that area - once past 1400
runs good. Thanks Pete
 
Probably what Newt said. Quite common. The thing that is curious is whether it has always done so. If it's a recent change, then something is going on and it's showing up as the idle circuit stumble.

Dan
 
Rough engine

I bought the plane last October - noticed it a couple of other times since .
Thought it was - maybe carbon build up on the plugs. Sometimes present other times runs perfect. In any event thank you all for your input and welcome all others as well.
Pete
 
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