Yanmar 2GM not reaching full rpm

[rchilders]

I have a Yanmar 2Gm on my S2 9.2C. It will not go over 2500 rpm under no load in neutral. Under load it will not go over 2100. I have ruled out the prop because of the under reving in neutral. What else causes a 2 cylinder diesel not to achieve full power?

 

[BobM]

Plugged mixing elbow.

 

[seedub]

I also have an issue reaching my rated PRM. I have a Yanmar 1GM10, and can only reach about 2300 RPM, when it should be about 3400 RPM. I just recently had to replace the injector pump (for an unrelated issue) and the fuel filter assembly. I have bled the system, but am somewhat baffled. Maybe it is drawing air into the system somewhere along the way? Not too sure.

 

[BobM]

Was it fine before the pump change? Sis you replace the washers if you removed any of the lines? My hose little copper washers are single use I understand. I suggest you repost on one of the main boards.

 

[SELou]

Check the throttle cable, I had a Tartan 10 with a similar problem (different engine). Fixed the cable, rpm's back!

 

[RichH]

Plugged mixing elbow.
Engine out of correct fuel timing.
Fouled, leaking or tip damaged injectors
Failing injection pump.
Incorrect/faulty tachometer.