Yanmar 2gm white smoke low rpm

[Captryan23]

My yanmar 2 gm will start fine and run to 3500 rpms in neutral and reverse. When I put it in forward it will only go to 2500 rpms and pump out white smoke. Any ideas?


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[DeepFrz]

Have you done any searching on the forum about the problem? There must be 20 or more threads on this type of problem and you have only given us enough info for us to start playing 20 questions.

[Captryan23]

Thanks for your reply. I did search and I did find some similar issues. The unique thing is that the problem is only in forward. Reverse and neutral are fine. I have the same problem in the slip or open water. I do have a max-prop that may be fouled. I hope to dive on it ASAP.


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[DougR]

The 2GM transmission has different ratios between forward and reverse for the 2.2:1 and 2.6:1 gear boxes. Both of these transmissions have 3:1 reductions for reverse, which means that in reverse gear there is significantly less prop shaft RPM than in forward gear, hence less engine load than in forward gear.

Clean the prop and boat bottom and try it again.

DougR

[DeepFrz]

It could be a dirty prop or over propped situation but if cleaning the prop doesn't fix the problem have a diesel shop clean and calibrate your injector(s). White smoke is generally unburnt fuel or water in the combustion gases. Black smoke is generally when your engine is overloaded. However because you can't get anywhere near your high rpm when in gear it could just be a dirty prop. If you put your hand in front of the exhaust outlet when running hard does it smell like diesel fuel afterwards? That is one indication of unburned fuel.

[Captryan23]

Great suggestions. I will put the wetsuit on tomorrow and clean the prop first. If no joy, I check injectors and exhaust. Thanks.


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[Captryan23]

Ok, I checked on prop and it was fouled. Cleaned shaft and prop, but have the same problem. Still have good rpms in neutral and reverse (3600), but only 2600 rpms in forward and some light smoke and soot on the water. So far I have:

Pulled injectors and they pop and spray good
Pull elbow and it is clear
Replaced all fuel filters
Checked oil level
Checked air filter. Parts of the foam was missing. I checked but did not see any blockage
I have a 2 blade feathering max prop

Any ideas????




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[ramseydt]

Did you ever resolve this issue? I am having the same issue now. I have been able to get the engine up to speed with the gorilla prop in the past. Just had the prop cleaned. Don't think this is the issue.

[ramseydt]

Gori prop not gorilla. Darn spell checker.