Engine runup problem

[carusoam]

OM,

Does it seem like it is running normal, but the rpm gauge is reading low.  Or can you sense that it is really low RPM at full throttle?

Most mooneys have their prop govenor fail in the fine pitch mode (high RPM).  (missiles and rockets fail in full feather mode)

If you are going to full power, and only indicating 2.200 RPM, I would be thinking that the

[1] RPM gauge is not working

Do you have access to a handheld tach?, There is a laptop application that can use engine sound for rpm measurement.

[2] the prop control is stuck. 

Visual check without the engine runing - look under the cowling for full motion of the control arm.  it would be an unusual failure mode of the prop controller to keep pressure on the prop.

[3] Full fuel is not making it to all of the cylinders.?  EGT would peak and then drop off (run LOP).  I expect that it would still try to get to full RPM, fitfully.

[4] Valve sticking or loss of compression.? 

(This comes with pretty high vibration and can be checked by compression test - as Dave recommended above).  Stuck or bent valve will seem to run-up well, but not give full power.

For [1] and [2] these are things you can check yourself for [3] and [4] it is a good time to schedule with your A&P before things become more serious....

-a-

Best regards,

[outermarker]

heading into the shope tomorrow. The plugs were cleaned, gap checked and a compression check last month. The plugs were good and compressions were all around 76/80. I guess the injectors will be looked at next.

[DaV8or]

Quote: outermarker

heading into the shope tomorrow. The plugs were cleaned, gap checked and a compression check last month. The plugs were good and compressions were all around 76/80. I guess the injectors will be looked at next.

[outermarker]

It was a fuel injector!!! One injector had a blockage. Once all the injectors were cleaned the engine ran like the engine I once knew. I am surprised at how simple the injector is to clean and how it is made. Thanks all for the suggestions. I am new to this engine. this forum is great!!!

[MooneyMitch]

Congratulations!  What a great feeling.

[Jsavage3]

Quote: bgpilot1

... and leave the mixture lean when landing as well.