2GM - RPM's

[Capt. Pen]

Have 2GM (1983), hours ?. Starts and runs with NO problems except; in neutral - 2900 RPM max. and in gear - 2900 RPM max. Exhaust elbow is clean, no evidence of improper burning (no soot or color), intake clear. Yanmar manual says, 3600 RPM in neutral and 3000 to 3200 RPM max. loaded. Tach ?, even if it is bad I would expect 2 different bad readings. Any ideas?

 

[red coles]

Not mine

I have a '85 2GM20. I can rev to 3900 rpm no load and appx. same under load. If your engine has always been this way,my thought is throttle cable problems. Try disconnecting cable at pump, and advancing by hand. Hope this helps Good luck red

 

[DON]

TACH

10 to 1 it's your tach. The govener will hold your RPM at it's max, which is usually 10% over red line. Unless you are swinging a really big prop, the engine should make max RPM in or out of gear. Tachs are not nearly as accurate as people think they are (unless you have calibrated it).