Yanmar 2QM15 was working fine at the end of the last season. I was all set motor over to haul-out and paint today, but couldn't get the engine to start-up. The only change from last year was the replacement of the fuel pump (attempt to prevent future problems). I have bled all the air from the lines (as I've done many times before). I'm certain the new pump is correctly installed because fuel pours out of the fuel filter bleed screw and injector nuts when manually pumped and when cranking by key. I noticed the fuel was rather cloudy so I pumped-out all but a few ounces out of the tank and replaced with 10 gallons of fresh diesel and changed the primary and secondary fuel filters. Still no go. In frustration I pulled the old WD40 trick and sure enough the engine runs like a top when receiving WD40 straight through the air intake. My only belief is that the fuel is still bad, or that it's time to inspect/replace the fuel injectors. Any ideas???
Fuel, injector, or what?
- Thread starter mjmulleriii
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Bleed at the Injectors
Have you tried loosening the fuel line nuts one at a time at the injectors; turning it over so you get fuel flow completely to the injectors, then re-tighten and do the second injector. Check the Yanmar ot Torreson web sites for more detail for your specific motor.
Have you tried loosening the fuel line nuts one at a time at the injectors; turning it over so you get fuel flow completely to the injectors, then re-tighten and do the second injector. Check the Yanmar ot Torreson web sites for more detail for your specific motor.
No air in the lines
Yep, tried that. I am 100% certain there is no air remaining in the lines. Nothing but fuel comes out all the way through to the injectors. I fear that the injectors may be clogged and in need of repair.
Yep, tried that. I am 100% certain there is no air remaining in the lines. Nothing but fuel comes out all the way through to the injectors. I fear that the injectors may be clogged and in need of repair.
Squirt
If you're getting a squirt of fuel from the infector line nuts when you just crack them and crank the engine, then you probably have sufficient pressure to run. You also have then proved that you have fuel delivery through the injection pump. Since the engine runs on WD 40, everything else is OK, leaving bad injectors as the final culprit. They are probably clogged with garbage from the old fuel, and possibly rusted as well from water in the fuel. Yank 'em and rebuild.
If you're getting a squirt of fuel from the infector line nuts when you just crack them and crank the engine, then you probably have sufficient pressure to run. You also have then proved that you have fuel delivery through the injection pump. Since the engine runs on WD 40, everything else is OK, leaving bad injectors as the final culprit. They are probably clogged with garbage from the old fuel, and possibly rusted as well from water in the fuel. Yank 'em and rebuild.
Fuel timing????
you sound like you are an old hand at fuel systems so don't take offense. Clearly the engine runs on WD40 and (I assume) stops when you stop feeding it through the intake manifold. This would mean that fuel is not being delivered or is being delivered at the wrong time. Since the fuel flow up to the injectors is OK then it is either all the enjectors decided to get plugged at the same time or the injectors are all injecting at the wrong time. I find it unlikely that all the injectors would get plugged at the same time even if you did have bad fuel. I'd bet on the injector timing being off. Good luck and let us know when you get it started as feedback is always nice for the archives.
you sound like you are an old hand at fuel systems so don't take offense. Clearly the engine runs on WD40 and (I assume) stops when you stop feeding it through the intake manifold. This would mean that fuel is not being delivered or is being delivered at the wrong time. Since the fuel flow up to the injectors is OK then it is either all the enjectors decided to get plugged at the same time or the injectors are all injecting at the wrong time. I find it unlikely that all the injectors would get plugged at the same time even if you did have bad fuel. I'd bet on the injector timing being off. Good luck and let us know when you get it started as feedback is always nice for the archives.
Bill
if the engine was running on water contaminated fuel at the end of last season, the injectors will surely be rusted from sitting all winter and will all "fail" at the same time. It's not as if the engine just died...it won't start after a) sitting all winter, and b) having the filters and lift pump changed. Either there is a lift pump problem or the injectors are fouled. I do not see how a timing issue could creep in to the mix as the timing components were not disturbed.
if the engine was running on water contaminated fuel at the end of last season, the injectors will surely be rusted from sitting all winter and will all "fail" at the same time. It's not as if the engine just died...it won't start after a) sitting all winter, and b) having the filters and lift pump changed. Either there is a lift pump problem or the injectors are fouled. I do not see how a timing issue could creep in to the mix as the timing components were not disturbed.
Fuel pump?
I do believe it could be an injector problem. I am just hesitant at pulling the injectors myself or spending the $ on getting a qualified mechanic to do it (rather pricey in Baltimore). It's probably too late to try mixing-in an injector cleaner. Also, shouldn't the engine still operate (albeit poorly) if the issue was merely water/impurities in the fuel? The old fuel was almost black in color. What could possibly be a reason for improper timing??? Thanks a million for the discussion. It eases the anguish.
I do believe it could be an injector problem. I am just hesitant at pulling the injectors myself or spending the $ on getting a qualified mechanic to do it (rather pricey in Baltimore). It's probably too late to try mixing-in an injector cleaner. Also, shouldn't the engine still operate (albeit poorly) if the issue was merely water/impurities in the fuel? The old fuel was almost black in color. What could possibly be a reason for improper timing??? Thanks a million for the discussion. It eases the anguish.
Try this!
I recently changed the fuel filters on my diesel tractor and it wouldn't start. After many bleedings and much ado, a mechanic told me to soak a rag in regular gas and hold it over the air intake while cranking. The engine coughed and choked but finally started to run smoothly. Be careful to keep a good hold on the rag, the suction can take it away from you.
I recently changed the fuel filters on my diesel tractor and it wouldn't start. After many bleedings and much ado, a mechanic told me to soak a rag in regular gas and hold it over the air intake while cranking. The engine coughed and choked but finally started to run smoothly. Be careful to keep a good hold on the rag, the suction can take it away from you.
WD40
Now that I think about it more, the gas rag trick sounds just like spraying the WD40, and that works only as long as the spraying continues. Then the engine dies off on its own.
Now that I think about it more, the gas rag trick sounds just like spraying the WD40, and that works only as long as the spraying continues. Then the engine dies off on its own.
Pull the injectors
If you're positive you properly bled the fuel line nuts at the injectors and got fuel, then the high pressure pump is working and its time to unbolt the two bolts(each) that hold the injectors into the cylinder; remove them and UPS them to any diesel service facility that can test and/or replace them(about $100/ea)replaced. You may need a wire pic and a small mirror to see and remove the shields that tend to stay in the injector hole. You should use a torque wrench to reinstall them to propper spec.
If you're positive you properly bled the fuel line nuts at the injectors and got fuel, then the high pressure pump is working and its time to unbolt the two bolts(each) that hold the injectors into the cylinder; remove them and UPS them to any diesel service facility that can test and/or replace them(about $100/ea)replaced. You may need a wire pic and a small mirror to see and remove the shields that tend to stay in the injector hole. You should use a torque wrench to reinstall them to propper spec.
It works
Pulled the injectors. Used 1/2 can of carb/gumbout cleaner and wala... put it all back together and it works even better than last year....
Pulled the injectors. Used 1/2 can of carb/gumbout cleaner and wala... put it all back together and it works even better than last year....
Marvin - Congratulations!
Your suspicions were right! And thanks for posting your results. Question: What did you do, if anything, about adjusting the injectors or timing when you re-installed them? According to the shop manual this seems like a critical step that would be reserved for a diesel mechanic.
Your suspicions were right! And thanks for posting your results. Question: What did you do, if anything, about adjusting the injectors or timing when you re-installed them? According to the shop manual this seems like a critical step that would be reserved for a diesel mechanic.
High PressurePump
If you didn't touch the high pressure pump, you didn't change anything on the injection timing. As I undestand it, the Injectors themselves are not adjustable, they operate on spring pressure, and 'pop-off'when the injected fuel reaches the required pressure. The carb cleaner probably cleaned out some minor deposits that were affecting the spray thru the tip, or just taking them out and cleaning the shields may also have affected the spray pattern. Usually anything that clogs the injectors can also clog the injector pump, so this appears to have been a less expensive fix than messing with the high pressure pump..
If you didn't touch the high pressure pump, you didn't change anything on the injection timing. As I undestand it, the Injectors themselves are not adjustable, they operate on spring pressure, and 'pop-off'when the injected fuel reaches the required pressure. The carb cleaner probably cleaned out some minor deposits that were affecting the spray thru the tip, or just taking them out and cleaning the shields may also have affected the spray pattern. Usually anything that clogs the injectors can also clog the injector pump, so this appears to have been a less expensive fix than messing with the high pressure pump..
Thanks for the Good Explaination
Based on Marvin's experience, i.e., the great improvement, this will be a project I think I'll add to my To-Do list this year, to take them out and have them inspected. Years ago I replaced the hydraulic lifters in a car and it made a tremedous improvement in the way the engine ran. Some of the old lifters were full of crud and one had the spring actually sideways so it wasn't working at all. Since the spray tip on the injector is extreemly important in the way the fuel burns maybe I might see an improvement here too. I know, if it ain't broke don't fix it, but it's good to stay ahead of the problems. Marvin's story here gives me incentive. The way he jumped in with both feet and just did it is impressive.
Based on Marvin's experience, i.e., the great improvement, this will be a project I think I'll add to my To-Do list this year, to take them out and have them inspected. Years ago I replaced the hydraulic lifters in a car and it made a tremedous improvement in the way the engine ran. Some of the old lifters were full of crud and one had the spring actually sideways so it wasn't working at all. Since the spray tip on the injector is extreemly important in the way the fuel burns maybe I might see an improvement here too. I know, if it ain't broke don't fix it, but it's good to stay ahead of the problems. Marvin's story here gives me incentive. The way he jumped in with both feet and just did it is impressive.
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