You may very well have some air trapped in the system. Try starting it at full throttle, be ready to throttle it back if it starts.
Bleeding Yanmar Injectors
- Thread starter mnmpizza
- Start date
Walbro low pressure (6-9psi) marine pump. Replaced the Stewart Warner low pressure marine pump that was installed around 1992. I may have replaced a perfectly good pump, but it was 30 years old so not a biggie.
That's an electric pump. Now we are getting some where.
Are you sure the electric pump is delivering fuel to the engine?
It's on demand so not continuous. I connected it to the tank, pointed the outflow into a bucket, connected it directly to DC power, and it pumped. That's just a lift pump. I do not know how to ops check the pump on the engine. These boats did not have a factory installed lift pump. They relied on the engine pump.
Are you providing power to the pump while cranking the engine?
Do you have shore power and a functioning battery charger?
Roger on both. I have two house batteries and an isolated starting battery. Both sets are on a smart charger.
Success. Pushed the throttle up with the shaft disengaged and it kicked over. Pulled it back to 2/3rds then 1/3rd then idle...slowly. Also engaged the prop shaft to put a good load on it. Left it at 1800rpms and slowly brouht it down to idle, then into reverse. Put it back to 2/3rds power but when I brought it back down to idle too quickly, it died. But the problem now is there's a knocking or "tinny" sound, kind of like a Model A or the African Queen. Disregard the fan belt that seems too loose in the video. Question is, is this where I quickly untighten and then retighten the bleed valves at the injectors? Is the sound indicative of a bubble in the system, or something more major?
I think I would try quickly opening and closing the lines at the injector, just as you suggest. When you do, note the rpm change for each cylinder. They should all drop the same amount.
The motor really shouldn't die just because you returned the throttle to idle quickly. I wonder if it's only running on 2 cylinders.
It's really hard for me to tell in the video. Almost sounds like normal diesel noise, maybe a little loud. One thing that does worry me is that the motor previously shutdown due to low oil pressure. That sound could be bad, like rod knock. Try putting it in forward gear at idle. Note the sound. Now go to 3/4 throttle. Did the sound get noticeably louder or just faster? Louder is possibly a rod bearing.
The motor really shouldn't die just because you returned the throttle to idle quickly. I wonder if it's only running on 2 cylinders.
It's really hard for me to tell in the video. Almost sounds like normal diesel noise, maybe a little loud. One thing that does worry me is that the motor previously shutdown due to low oil pressure. That sound could be bad, like rod knock. Try putting it in forward gear at idle. Note the sound. Now go to 3/4 throttle. Did the sound get noticeably louder or just faster? Louder is possibly a rod bearing.
Have you or anyone else added fuel to the boat lately? Gasoline in a diesel will cause issues. I have not personally see the results, but I know the low cetane will cause starting issues and abnormal combustion, likely smoke & noise.
It did not get louder, just faster as we recall. I'll check again tomorrow or Wednesday.
Only added fuel at the end of last season. We top off the tank about every year or two. We get about 3-4 gallons per year...we sail more than motor, and the time from our slip to the Great Chesapeake is very short.
Does this motor have one compression release lever per cylinder? If it does, make sure all 3 are returned all the way to the normal position. This could cause just about all the issue you are having.