I'm having trouble bleeding my engine. Alot of people say their's fires right up, but mine will not. Any ideas? I'm running out, I have cranked it, seen fuel dribble out the injectors with no air bubbles, then shut them, but it will not start. I'm pretty sure the line from tank to injectors is airtight; I think maybe the mechanical fuel pump attached the crank shaft is not pushing fuel through with a strong enough pressure. That's my only idea. Josh
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be sure...
Josh, hope things are good. bleeding that engine should do it. So let me go over some points. have someone help you. they can turn the engine over with the starter while you bleed. dont loosen the injector when the engine is not turning. roll the engine, while its turning crack one enjector open just a bit untill fuel squrits out with no bubbles then quickly shut it. Only then do you stop cranking. Its important not to stop turning the engine till you closed the injector. or open it when it is not turning. The fuel should squirt out pretty hard. If you think it is the fuel pump, try this first. Install an electric fuel pump in line with the exixting pump. put a separate switch on it so it only runs when you want it too. You normally wont use it. but when you change filters or bleed the engine it makes life alot easier. I agree that those engines dont normally require much bleeding but try it this way. If you already havent done it.
Josh, hope things are good. bleeding that engine should do it. So let me go over some points. have someone help you. they can turn the engine over with the starter while you bleed. dont loosen the injector when the engine is not turning. roll the engine, while its turning crack one enjector open just a bit untill fuel squrits out with no bubbles then quickly shut it. Only then do you stop cranking. Its important not to stop turning the engine till you closed the injector. or open it when it is not turning. The fuel should squirt out pretty hard. If you think it is the fuel pump, try this first. Install an electric fuel pump in line with the exixting pump. put a separate switch on it so it only runs when you want it too. You normally wont use it. but when you change filters or bleed the engine it makes life alot easier. I agree that those engines dont normally require much bleeding but try it this way. If you already havent done it.
One idea Josh.
I think it is time to pay a Yanmar mechanic Josh. You need someone with the gauges to measure fuel pressure. Not only is there the fuel pump question there is also the injector pump to consider. And not just fuel pressure but also fuel timing. Those cannot be fixed by bleeding.
I think it is time to pay a Yanmar mechanic Josh. You need someone with the gauges to measure fuel pressure. Not only is there the fuel pump question there is also the injector pump to consider. And not just fuel pressure but also fuel timing. Those cannot be fixed by bleeding.
Bleed at the filter, too!
Josh, you didn't mention bleeding at the filter bowl. That is just as important as the injectors. You're close. There is a bleed screw on the top of the filter housing. First, crack it and run the fuel through with the lift pump lever located on the fuel pump until it stops bubbling. I hope that's it. Also bleed the fuel compression block and,lastly, move to the injectors doing the aft-most injector last). Also look at the attached link. I hope the other people offered to help you since they claim that their engines are OK.
Josh, you didn't mention bleeding at the filter bowl. That is just as important as the injectors. You're close. There is a bleed screw on the top of the filter housing. First, crack it and run the fuel through with the lift pump lever located on the fuel pump until it stops bubbling. I hope that's it. Also bleed the fuel compression block and,lastly, move to the injectors doing the aft-most injector last). Also look at the attached link. I hope the other people offered to help you since they claim that their engines are OK.
Bleed alternative
To avoid or at least reduce the need to bleed, use a West System syringe and inject fuel into the bowl until it overfills. This is often sufficient to preclude the pumping altogether. But it's good advice to examine both filter bowls.
To avoid or at least reduce the need to bleed, use a West System syringe and inject fuel into the bowl until it overfills. This is often sufficient to preclude the pumping altogether. But it's good advice to examine both filter bowls.
ok we will try another
try breaking the fuel line after the pump and before the engine. Turn on the electric pump and see what you get. then turn over the engine and see what happens. It should run a strong steady stream with the elec pump on. If it doesnt you may have a clog you dont know about or a bad elec. pump. but start at the tank and rule out problems. Another trick to find and air leak is to take teh fuel line off at the tank and put a bicycle pump on it. the air pressure will show you any leaks in the system. let us know...
try breaking the fuel line after the pump and before the engine. Turn on the electric pump and see what you get. then turn over the engine and see what happens. It should run a strong steady stream with the elec pump on. If it doesnt you may have a clog you dont know about or a bad elec. pump. but start at the tank and rule out problems. Another trick to find and air leak is to take teh fuel line off at the tank and put a bicycle pump on it. the air pressure will show you any leaks in the system. let us know...
Another Check
Josh I pass this on from expensive experience. When my 3QM30 would not start I tried all the suggestions listed below. Nothing worked. It turned out it had nothing to do with the fuel. It was a plugged exhaust riser. Check the riser (gooseneck, mixer) on your exhaust where the water is injected into the exhaust. If that riser is badly rusted (on the inside) it might be your problem. The riser needs to be replaced very 5 years or so. As the rust builds up it plugs the exhaust. It was an expensive exercise for me of engine repair that was not necessary. The so called "repair" was done by a qualified Yanmar mechanic who never thought to check the exhaust. It takes 5 minutes to check and may be the answer. No harm in looking. Fair winds. Don
Josh I pass this on from expensive experience. When my 3QM30 would not start I tried all the suggestions listed below. Nothing worked. It turned out it had nothing to do with the fuel. It was a plugged exhaust riser. Check the riser (gooseneck, mixer) on your exhaust where the water is injected into the exhaust. If that riser is badly rusted (on the inside) it might be your problem. The riser needs to be replaced very 5 years or so. As the rust builds up it plugs the exhaust. It was an expensive exercise for me of engine repair that was not necessary. The so called "repair" was done by a qualified Yanmar mechanic who never thought to check the exhaust. It takes 5 minutes to check and may be the answer. No harm in looking. Fair winds. Don
Josh goes sailing!
And the engine is running!! I chime in only because I think Josh only gets on HOW when at school. I talked to him today and it was a bleed problem. I will let him tell the story. It's 15 degrees here and I am helping him sail!? Doesn't seem fair.
And the engine is running!! I chime in only because I think Josh only gets on HOW when at school. I talked to him today and it was a bleed problem. I will let him tell the story. It's 15 degrees here and I am helping him sail!? Doesn't seem fair.
Got it goin
Thanks for the tips everybody. My problem was that I was bleeding the engine incorrectly. I was bleeding the engine at the nut above the filter and the nuts at the injectors themselves--on the top of the engine, directly above each injector. A friend who worked on diesels showed me this and it has worked every other time I needed to bleed. This time, I talked to a Yanmar mechanic on the phone, and went over to his shop where he showed me how to properly bleed an engine. (For all the people in the S.F. Bay area, List Marine in Sausalito--great people, although extremely intolerant of dissenting opinions) He said don't use the starter; use the manual fuel pump--the small lever attached to the fuel pump on the engine. This lever provides 7 or 8 pounds of pressure to the fuel line. So you push the lever a bunch of times, crack the nut on the fuel filter, push the lever some more, get fuel to spurt out, and shut it while you're pumping the lever. Then--this was my problem--I missed the second bleed point, which is on the fuel injection pump, not at the injectors themselves. I had an air bubble in there, but once I cracked that nut, and pushed the lever a few times, fuel spurted, shut the nut, I was good to go. He said not to even bother bleeding at the two injectors themselves. After that, I was out for the day sailing, me, my cousin, and some ten-foot swells. Thanks again for all the help. Josh
Thanks for the tips everybody. My problem was that I was bleeding the engine incorrectly. I was bleeding the engine at the nut above the filter and the nuts at the injectors themselves--on the top of the engine, directly above each injector. A friend who worked on diesels showed me this and it has worked every other time I needed to bleed. This time, I talked to a Yanmar mechanic on the phone, and went over to his shop where he showed me how to properly bleed an engine. (For all the people in the S.F. Bay area, List Marine in Sausalito--great people, although extremely intolerant of dissenting opinions) He said don't use the starter; use the manual fuel pump--the small lever attached to the fuel pump on the engine. This lever provides 7 or 8 pounds of pressure to the fuel line. So you push the lever a bunch of times, crack the nut on the fuel filter, push the lever some more, get fuel to spurt out, and shut it while you're pumping the lever. Then--this was my problem--I missed the second bleed point, which is on the fuel injection pump, not at the injectors themselves. I had an air bubble in there, but once I cracked that nut, and pushed the lever a few times, fuel spurted, shut the nut, I was good to go. He said not to even bother bleeding at the two injectors themselves. After that, I was out for the day sailing, me, my cousin, and some ten-foot swells. Thanks again for all the help. Josh
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