Yanmar loses power, slows down & kills

[tallyho8]

When it started slowing down a lot, I would loosen the line to each injector one at a time. Each time it would slow down more and kill. I noticed no difference from one injector to the other.

It does seem to be blowing a little more blue smoke out the exhaust when running at full speed but not noticible at lower speeds. No smoke comes out the crankcase breather.

And yes, it has a plastic fuel bowl, not a glass one, and I have changed the o-ring. I even put a can of fuel on the hood and ran a line down from the can to the bleeder valve on the injector pump, eliminating the fuel filter assembly and tank and hoses and it did the same thing.

My next decision is whether to use a 5 pound hammer or a 7 pound hammer on it.

I searched many old threads looking for something similar and almost all threads ended without the person telling what they did to correct the situation, if if was corrected.

 

[greatrandini]

[
I searched many old threads looking for something similar and almost all threads ended without the person telling what they did to correct the situation, if if was corrected.[/QUOTE]


I replaced the hard plastic fuel bowl, o ring and filter when my unit had the same symptoms. It was only a couple bucks.

 

[BruceR]

I know you've checked everything over. Whenever I see blue smoke it tells me it's time to wring the water out of the fuel filter. Since you've gone through the fuel system, is there any chance it's time for a head gasket ?

Bruce

 

[kenmac]

if it were white smoke I would say water . Blue smoke possibly oil

 

[BruceR]

if it were white smoke I would say water . Blue smoke possibly oil

OK- Light bluish/white smoke

Bruce

 

[tallyho8]

It's a little difficult to tell the exact color of the smoke but I have checked everything that I know how to check and everything I check seems ok.

It seems that if my head gasket was bad that my water in my radiator would not look so clean with no bubbles and that my oil would show signs of water in it. If it was my rings, would it run great sometimes and bad others? And wouldn't it have some blowby into the crankcase? Could a bad valve or a bad valve setting cause this problem?

LMTC may be right about it being a bad injector even though the engine slows down when I loosen the line to each injector but I hate to spend the time and money buying new injectors if this is not the problem.

I'm wondering if I ought to take off the valve cover and check things out but then I have to order a new gasket first.

Is it possible for the injector pump to get out of timing and make it run like this?

The mechanics I have checked with in this area have never worked on a Yanmar before and don't encourage me to bring it to them. I wonder if there is a good Yanmar mechanic within 100 miles for me to take it to.

 

[1danny]

It's a little difficult to tell the exact color of the smoke but I have checked everything that I know how to check and everything I check seems ok.

It seems that if my head gasket was bad that my water in my radiator would not look so clean with no bubbles and that my oil would show signs of water in it. If it was my rings, would it run great sometimes and bad others? And wouldn't it have some blowby into the crankcase? Could a bad valve or a bad valve setting cause this problem?

LMTC may be right about it being a bad injector even though the engine slows down when I loosen the line to each injector but I hate to spend the time and money buying new injectors if this is not the problem.

I'm wondering if I ought to take off the valve cover and check things out but then I have to order a new gasket first.

Is it possible for the injector pump to get out of timing and make it run like this?

The mechanics I have checked with in this area have never worked on a Yanmar before and don't encourage me to bring it to them. I wonder if there is a good Yanmar mechanic within 100 miles for me to take it to.

If you live close to Denham Springs, call Sams Diesel Service, he buys a fair amount of Yanmar parts from me. 225.665.1346.

Danny

 

[kenmac]

The mechanics I have checked with in this area have never worked on a Yanmar before and don't encourage me to bring it to them. I wonder if there is a good Yanmar mechanic within 100 miles for me to take it to.






Do you have a deere dealer around. The deere dealer here told me they would work on mine if I couldn't repair it myself

 

[LMTC]

It's a little difficult to tell the exact color of the smoke but I have checked everything that I know how to check and everything I check seems ok.

It seems that if my head gasket was bad that my water in my radiator would not look so clean with no bubbles and that my oil would show signs of water in it. If it was my rings, would it run great sometimes and bad others? And wouldn't it have some blowby into the crankcase? Could a bad valve or a bad valve setting cause this problem?

LMTC may be right about it being a bad injector even though the engine slows down when I loosen the line to each injector but I hate to spend the time and money buying new injectors if this is not the problem.

I'm wondering if I ought to take off the valve cover and check things out but then I have to order a new gasket first.

Is it possible for the injector pump to get out of timing and make it run like this?

The mechanics I have checked with in this area have never worked on a Yanmar before and don't encourage me to bring it to them. I wonder if there is a good Yanmar mechanic within 100 miles for me to take it to.

Mechanic should not need to have Yanmar specific familiarity to diagnose this problem. Unless I've missed something, what you have referenced this happens AFTER app. 10 minutes run time.....so something is changing. Most obvious change in 10 minutes is some parts get hot. I would start with that assumption and look at those things that might change when hot. A fuel filter doesn't get hot. Assuming it's not a vent issue with the tank, it has to be from the pump to the engine. Keep in mind that I personally am the anti-mechanic....I pay good people because my mechanical knowledge would fit in a very small place....but I pick up stuff by listening. I know we had one unit that ran fine for 5-10 minutes and then ran very rough to the point of stalling. Several things were checked, injectors removed and cleaned, symptom seemed to clear up, but returned shortly. Eventually replaced one injector, end of problem. For whatever reason one injector was getting fouled quickly, and did so repeatedly. Wasn't a fuel issue, just a bad injector, and it only malfunctioned after running several minutes. I have no idea why, and I recall it left the mechanic scratching his head too....but the problem went away with a new injector.

 

[jimmer2880]

I know that this is WAY off in left field. But.....

Some yanmars, run their regurn fuel into a collection bowl (for cold starting), then back into the tank. What would happen if that return line was somehow partially clogged? On startup, the line would have no pressure, but after running for a bit, it would fill up and there wouldn't be any room for the return to go.

But, if that was the case, I guess there would be lots of black smoke from unburned fuel.

On second thought, nevermind - wasn't a good idea after all.