My M25 engine will not operate great than 2200RPM with the transmission in neutral.
Below are the things I have done so far:
[LIST]
[*]Checked the engine RPM with a hand held tachometer (several times) to confirm accuracy of tack.
[*]Checked throttle cable travel that throttle linkage goes to the throttle stop on the engine.
[*]Replace fuel injector pump.
[*]Injectors have been removed and serviced by a injector shop.
[*]Replaced exhaust hose to ensure no blockage.
[*]Adjusted the throttle stop screw on the front of the engine above water pump.
I’m now looking at the governor as being the problem
Any suggestions
—
Keith & Donna
SV: Victoria Dos
Hull #431
Sea of Cortez, Mexico
Kieth,
Sounds like you have wrestled with this a while and spent a few bucks.
When motoring is 2000 RPM the max RPM you get as well as out of gear?
If so I may concure on your govoner prognosys, if it is less than 2000 RPM I would look for a restriction in the fuel system, filters, pinched or kinked line, collapsed or clogged pick up in the tank or restricted vent line limiting the fuel flow to the engine.
The govoner is a very robust component and it would be hard to invision it failing. When you adjusted the stop on the rack ( this is the screw above the water pump) did it do any thing? It obviously did not increase RPM when you backed the set screw out, did it decrease when you ran the set screw in?
Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas
Did you check the mixing elbow in the exhaust system? They commonly clog up and can cause this problem.
Good call Bud, I quickly scaned Kieth's trouble shooting to date and read that he replaced the exhaust hose and in my mind assumed he was talking elbow. The elbow would be the #1 suspect, like us the engine needs to breath, it can not inhale if it can not exhale first.
Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas
Hi - on a previous boat of ours we encountered a similar problem with not being able to obtain full RPM out of the engine (it was a Yanmar).
Have you checked your compression readings on each of the cylinders?
What colour is the exhaust? (Is it white, sooty, etc.)
You may have a leaking head gasket that is affecting compression and the ability to generate max RPM.
We went through $$$$ of inspections, replacements, etc - and the very last thing was the head gasket - which was ultimately the problem all along as everything we checked came back fine.
Hope that this may help a little in your diagostics.
Brett Colville
Ceiba I - Toronto
2006 Catalina 36 Mk II # 2299
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