Yanmar loses power, slows down & kills

[California]

They are very common in marine and generator applications.

And the ThermoKing refrigeration units you see high on the front of semitrailers. Find a shop that services those, and I'll bet they can refer you to Yanmar injector and pump service.

 

[tallyho8]

Underwaterdog: I may have confused things by calling them primer pumps. Actually they are not pumps but they are spring loaded bleeder valves where you just push the valve with your thumb to bleed the line instead of having to remove a bleeder screw.

To make things even more confusing, I took the fuel return lines off the top of my injectors yesterday. As I understand it, the fuel return lines take the excess fuel that is pumped to the injectors and return it first to the thermostart and then to the fuel tank.

Observing the lines when I start the engine and it is cool and running well, there is a very minute amount of fuel drops coming out of each injector. As the engine warms up and starts running bad, there appears to be the same amount of fuel coming out of each injector. If the injection pump was not pumping properly, it seems to me, that there would be no excess of fuel going to the injectors to come out of the fuel return line.

I am beginning to think I have something wrong with cylinders 1 & 2 instead. I took my valve cover off last night and checked the valve gaps and they were all fine. I could not believe how much oil it pumped when I started my motor with the valve cover off. Now I have to clean my tractor and engine again.

Even though an expert told me my injectors were good, I am going to change the injector in cylinder 1 with the injector in cylinder 3 today and see if anything changes.

The DW is getting upset with me spending this much time on the tractor as it is Mardi Gras season and she wants me to bring the grandson to some parades There are just not enough hours in the day right now for me to learn how to be a diesel mechanic. This is why I bought a Yanmar, to avoid working on the tractor.

 

[Underwaterdog]

There are just not enough hours in the day right now for me to learn how to be a diesel mechanic. This is why I bought a Yanmar, to avoid working on the tractor.

I can relate to your frustration. Sometimes when I run in to something that is racking my brain, its best to walk away from it for a while, and come back and start over. That is a good idea to rule out the possibility of an engine issue, because depending on where a head gasket is leaking, it can give many different symptoms. It does not always leak combustion materials into the cooling system, or water into the oil. A quick way to check for engine trouble is a compression check. And since this is happening after the engine is warm you probably need to do it after the engine has warmed. My american ITT manual does not give any information on doing a compression check. If anyone who is reading this knows how to do the compression check please chime in. I found a link to a generic troubleshooting chart for diesels. Its says the pressures run 3000 to 4500 psi, so you may need a special gauge and fitting to do this. Diesel Engine Diagnostics DEET 5
Meanwhile, go to the Mardi Gras parades and have some fun with the GS . They grow up fast.

 

[rock2610D]

Are injectors seated properly? Were they torqued down to spec. when you reinstalled? Check for compression leaking between injector and cylinder head. Did you remove top portion of injectors? The part that the return hoses clamp to. Could there be a blockage there?

Have you bled the system correctly? Air pockets can be very fussy sometimes.

By correctly I mean as per the manual for your tractor, not a sub for an american models manual.

I have 3 manuals for my 2610D. 1 for the engine which is a 3T80 and that manual is for a JD 850. I also have a 336D Yanmar manual for powershift tans and such, plus a JD 950 manual for the chasis. ALL THREE HAVE DIFFERENT METHODS OF BLEADING THE FUEL SYSTEM!

 

[tallyho8]

I just swapped my #1 and #3 injectors around with no difference. When it warms up it is not running on cylinder 1, runs poor on #2 and runs good on #3. This definitely eliminates bad injectors.

I wish it was easier to change the injector lines from cylinder #1 to #3. This would surely tell me if the injector pump was bad, but I would have to bend and destroy my injector lines to do this.

Now I am wondering if a head gasket could be bad between cylinders #1 and #2 but I don't understand why it would run perfect when cold and act up when it warms up.

There is a thread on Hoyes Tractor Support Forum started in November 2007 and the poster, jameswms, had the same problem and never posted if or how he got it fixed. He replaced the head gasket and it did not help. He thinks it is the injection pump. I wish people would finish threads!

 

[California]

I wish it was easier to change the injector lines from cylinder #1 to #3.

Wouldn't that make it fire (or at lest inject) out of time?

 

[SailorBob]

I wish people would finish threads!

If there is something wrong with the head or head gasket maybe it had to heat enough to cause the metal to expand and create the defect. When I rebuilt my engine I had the head magnafluxed and pressure tested. They resurfaced the head too.

Me too. I always try to report back my findings whether good or bad.

 

[kenmac]

I just swapped my #1 and #3 injectors around with no difference. When it warms up it is not running on cylinder 1, runs poor on #2 and runs good on #3. This definitely eliminates bad injectors.

I wish it was easier to change the injector lines from cylinder #1 to #3. This would surely tell me if the injector pump was bad, but I would have to bend and destroy my injector lines to do this.

Now I am wondering if a head gasket could be bad between cylinders #1 and #2 but I don't understand why it would run perfect when cold and act up when it warms up.

There is a thread on Hoyes Tractor Support Forum started in November 2007 and the poster, jameswms, had the same problem and never posted if or how he got it fixed. He replaced the head gasket and it did not help. He thinks it is the injection pump. I wish people would finish threads!

Did you ever locate anyone that would work on the tractor ?? I think you can have the injector pump tested

 

[ToadHill]

Just a thought, are you sure none of the fuel lines have collapsed. I've had rubber fuel lines that look good on the outside but collapsed on the inside. It was a heck of a problem to diagnose.

 

[YanmarFever]

Just a thought, are you sure none of the fuel lines have collapsed. I've had rubber fuel lines that look good on the outside but collapsed on the inside. It was a heck of a problem to diagnose.

Toad, thats what I thought was his problem too. The fuel lines are falling apart from the inside or the tank was dirty & clogging up things.

I wish he lived closer I would pack up the truck & drive there, though Im in Oregon & he's in Florida