2000 Merc 175 EFI no power when warm

[Eastwoodnorris]

My engine runs well when cold. Starts fine, planes boat out fine, good mid range and top end power. After it warms up, it wont plane out the boat. It still starts and idles good and has good power if I'm already on plane. It revs fine in neutral but when I put the throttle down it just dogs. Not sputtering, just powerless. If I run my jack plate up to have the prop spin and get the rpm's up, it will get up to power. The voltage regulators were replaced about 8 years ago and I'm wondering if I have a faulty stator.

 

[alldodge]

Howdy

Have you checked compression cold and warm?

 

[Eastwoodnorris]

Compression is 100-103 psi. I ohmed out the stator and the trigger and both are within spec. I do not have a DVA meter yet to check output voltage.I unplugged each coil one at a time and it had a definite negative effect with each coil (I'm not sure how to test the coils without replacing one at a time with a known good one). It sure seems like the engine is in limp mode. I checked the head temperature sensor as well.

 

[flyingscott]

What is the actual engine temp