Engine dies at idle

[pinball]

My yanmar 30 hp dies at idle when I put it in forward unless I idle it up. Goes great in reverse at idle ,not sure where to start the troubleshooting process any ideas would greatly be appreciated.

[a64pilot]

What is your idle RPM? Fwd is a higher load as the prop is more efficient and therefore pulls more power from the engine than reverse.

[Mycroft]

Yep, first check the RPMs at idle. That's what was wrong with my Perkins that was doing the same thing. The idle was set too low.

[pinball]

10000 rpm

[pinball]

It was about 790 then I ajusted to 10000

[SkiprJohn]

Originally Posted by pinball

10000 rpm

10000 is 10xs what you need. 800 to 1000 is good.

I'd check for fishing line, or dock lines wrapped around the shaft or prop or a severely encrusted propeller. If all is clear there then try turning your prop shaft by hand in the engine compartment (engine off). Feel if it is harder to turn clockwise or counter-clockwise.

[pinball]

Oops to many 0s thanks when I get back to the boat I'll jump in

[markpierce]

Prefer shifting gears on my JD 4045 at 800 RPM to make it easy on the transmission and engine mounts and propeller shaft universals.

[pinball]

Yup me to