Can't power up a 2GM20F Yanmar

[Wally]

I can't seem to power my 2GM20F beyond 2000 RPM. If going beyond 2000RPM I belch brown smoke and do not increase speed or RPM. I have done the following:1) Cleaned the air intake foam filter.2) Removed and cleaned the mixing elbow.3) Am in the process of having the injectors serviced.The injectors were serviced a year ago so I find it difficult to believe there is a problem here. The only other things that were done was the Racor fuel filter was changed in the fall. The engine fuel filter was not changed because the Racor was clean. Plastic fuel tank was kept full all winter. Boat is 10 years old.What's next?Thanks in advance for any help or comments.

 

[nick8481]

Prop

Does this happen in neutral or during powering up in gear.If no problem in neutral but low rpm's in gear try checking prop and clean it. nick

 

[Wally M]

Can'y power up 2GM20F

Sorry. Forgot item 4 on my original post. Bottom is clean and prop is not fouled.

 

[Pete]

some suggestions

I would suggest that you change the engine mounted filter also just as a percaution and to remove it as a possible cause. Also the filters should be of different density and the engine mounted filter should remove smaller particles.Might not be the problem but should be done anyway.This sounds like a elbow mixing problem so are you 100% that the elbow is clear? As Nick asked does it rev up OK out of gear? Did this just happen or has it been a problem that slowly developed? Try removing the air cleaner(only for testing) to be sure that you are not starving the engine for air.Check to see that you are getting full travel from the controls to the fuel pump and that the cable has not slipped or not opening the fuel pump all the way.Why were the injectors serviced last year and did anyone mess with the pump? Even thought you keep you fuel tank full check it for water and recheck the filters for any water. Recheck your recor fuel filter to be sure it is not sucking air. Did the engine run OK after the filter change? Sorry not a real good answer here just some suggestions,hope they are of some help.

 

[Wright Ellis s/v WhiskyII]

Pete's list

Pete is on the money. I worked for years as an auto diesel mechanic a learned that a diesel needs 1) air, 2) rotation ie proper cranking speed 3) clean fuel delivered at the proper moment in the proper amount.You have eliminated #s 1 and 2. Your problem is narrowing #3 down to the offending culprit and I'd start with the "clean" part as it is easiest for an owner to ascertain and fix.Brown smoke is indicative of build-up of particulates in the exhaust, not a problem with combustion (that'd be black smoke). Blue smoke=oil; white smoke=coolant.If fuel quality/quantity is not the problem than injection timing is what I'd check next.