High EGT at idle?

[Lood]

Lately, I've noticed that the #2 EGT is much higher that the other three when my engine is idling. I always lean aggressively for all ground operations, but this doesn't seems to make a difference. As soon as I increase the RPM during the run up, all EGT's level out, like normal and during all flight operations, all is normal.

When I close the throttle on landing, #2 goes higher again.

Anybody have an Idea where I can start looking?

[sleepingsquirrel]

I'm going with weak or broken exhast valve spring.

[Cruiser]

can you download the engine data and post it here for better analysis?

[Piloto]

Sounds to me like an intake leak. Check intake pipe gaskets and bolts. Intake leaks has a lesser effect at high power settings since the engine is getting more air through the pipe than from the leak.

José

[Lood]

Here's a data sheet of the first flight where I noticed it. However, looking at the actual data, it doesn't seem to be as bad as shown on the bar graph of the JPI. I'll check all the possibilities on the intake side.

I sure hope the exhaust valve spring possibility is incorrect - this engine has done only about 65 hrs since an extremely expensive overhaul.

Engine Data.pdf

[N201MKTurbo]

It could be one plug is misfireing, try a mag check at the low power setting to see if it is rough on one mag. The magneto power output is very low at low RPMs. With only one plug fireing the fuel charge burns slower and there is more residual heat when the exhaust valve opens, rasing the EGT.

[OR75]

or a bad egt probe ...

[sleepingsquirrel]

I'm going to stick with exhaust valve spring because of the aggressive leaning during ground operations.

I'm just guessing and hope it is simply an intake leak as well. I've heard that there are two springs on each valve, an inner and outer and that it is hard to see the inner spring when it is broken. By all means check the easy stuff first! I'm old and easily confused and don't have any money on the line.

[jetdriven]

im going with the flow divider is messing with the fuel flow at idle, it is not a measured parameter, and to ignore it. I would occasionally doa GAMI spread test and a GAMI hi-low test as well as inflight LLP mag checks to confirm the ignition, fuel and induction systems are tip top.

[sleepingsquirrel]

It could just be a sticky exhaust valve. I would try a little MMO for a while and see if the idle exhaust temp returns to normal.

[garytex]

Piloto's got it right again. Just had this symptom, intake leak at o ring at base of intake runner. Diagnose by spraying carb cleaner at potential leak points, rpms will go up when you hit a leak. wash off carb cleaner.