Jesse
Well Known Member
I have a plane here with a Lycoming O-360 that has been down for a panel upgrade. When we start the engine, Cylinders 1 & 4 drop out at Idle. At power (pretty much anything over 1,000RPM) the EGT's and CHT's come up, but at idle, they drop back out. It flew fine and made good power. The engine has 2-300 hours.
We checked for stuck valves and they are fine, not stuck or even a little sticky.
We can test new plugs, but the chance of having both plugs on two different cylinders dropping out the same is very low.
We have looked for intake leaks, and haven't completely ruled that out, but everything looks great on those cylinders.
Leaning out at idle doesn't change anything, but the RPM does increase significantly.
Any other thoughts, things to try?
We checked for stuck valves and they are fine, not stuck or even a little sticky.
We can test new plugs, but the chance of having both plugs on two different cylinders dropping out the same is very low.
We have looked for intake leaks, and haven't completely ruled that out, but everything looks great on those cylinders.
Leaning out at idle doesn't change anything, but the RPM does increase significantly.
Any other thoughts, things to try?
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