JD 850--no fuel delivering to middle injector

[Niji]

Hey Folks,

Hey Folks--so, I just replaced a head gasket and front crank seal on my JD850 (3 cyl Yanmar diesel). I only took the three metal fuel lines loose at the injectors--did not mess with the other ends or the injector pump at all. Got it all back together and now the front and rear cylinders are getting fuel when I crack and bleed them, but the middle one is not. It was running fine when I parked it to do the new head gasket. It seems like very odd timing for an injector pump to decide to poop the bed, and it also seems odd that I'd get fuel delivering fine to two cylinders but not the third. Any insights would be much appreciated--especially if they don't involve buying a new injector pump! (Just sayin'/hopin'). Thanks!

PS I originally posted this in the Yanmar section but no responses, and then I realized it probably belongs here in "Repairs." Sorry for the double posting if that's an issue.

 

[JRobyn]

Send a PM to scpumpguy. Most knowledgeable injection pump guy I've seen on here.

p.s. - correction; thepumpguysc (I always get that wrong).

 

[TimberHole]

When you say number 3 isn't getting fuel are you saying the line won't bleed or the fuel isn't getting thru the injector? When you bled the system did you do it with the throttle wide open?

 

[Spanner]

He's saying #2 isn't getting fuel when he 'cracks' it to bleed - as I read it.

Cracks it at the Inj'r connection probably as that's more accessible than at the FP connector.

Anything blocking the pipe from FP to Inj'r possibly? (Unlikely I know).

Working backwards, as we know fuel is going to #'s 1 & 3...

You need to remove the #2 pipe and see if fuel is discharged from the Fuel Inj.Pump itself
(This may require you to remove #1 or #3 pipe first.

Work 'clean' so no dirt can get into uncapped injectors - Or fit caps if you have any of any sort.

 

[TimberHole]

He's saying #2 isn't getting fuel when he 'cracks' it to bleed - as I read it.

.

Ha....sorry for the reference to number 3. I was thinking about the firing order and my typing was apparently faster than my brain!

I had a hard time bleeding my 950 the first time I did it and then realized later I only had the throttle cracked during the process. Worked a lot better when I opened the throttle all the way!

As for this 850 I can't help but wonder if the valve adjustment is off on number 2. That could obviously keep the cylinder from firing. Seems unlikely there is a fuel delivery issue to that cylinder if it was working fine before. Just a thought.

 

[Niji]

Hey fellas,

Thanks for the thoughts. So, I took the fuel line loose at the injector pump end to see if perhaps it was just a blocked line, but no--there is no fuel exiting the injector pump for the middle line. I'll certainly pm the "thepumpguy", so thanks for that, JRobyn.

I have the manual, and the exploded parts diagram makes it seem like if I remove the threaded cap where the fuel line attaches at the pump that there are some parts that I might be able to remove/clean/check without getting into the timing and all that deeper stuff? I'll keep studying and tinkering. I find it at least hopeful that the front and rear cyls are getting fuel fine.

 

[Spanner]

Ok. Well done so far. You have proved what I was asking you to which was to eliminate a blocked pipe at the FIP.

So, now we know fuel is getting to the FIP and able to exit at #1 & #3, thus there is a problem in the FIP around the #2 circuit.

Sorry it wasn't just a simple blockage in the line and it coincides with your other Cyl. Head work etc. That's just bad luck I suppose.

Keep us informed with your progress.

 

[Spanner]

http://www.tractorbynet.com/forums/yanmar/386119-jd-850-no-fuel-delivering.html#post4878014

 

[Niji]

Yes...I tried to delete the post in the Yanmar section when I realized it needed to be over here in "Repairs," but I couldn't find a way to delete the other post, so I'm doubled up I'm afraid. Perhaps a moderator has to do that?

 

[Niji]

Great news, friends! Problem solved! I called up to Hoye Tractor (in TX, who handle a lot of parts for this JD 850 and other such Yanmars) and the guy was experienced with this issue in this model. I also noticed on their website that they have a note in red letters explaining that these injector pumps will run for tens of thousands of hours unless you get bad fuel.

So they fella on the phone said to turn the motor over and tap the pump with a hammer. Then he said if that doesn't get it, turn the threaded cap (where the fuel line attaches) 1/4 turn loose. I had tapped on the pump while cranking it previously with no luck. But, he said that if two of the injectors are getting fuel that it almost certainly is water in the fuel that caused the plunger in #2 to stick, and a little knocking on it should get it going.

So I got the wife to turn the key while I tapped. Nothing. I fetched a hitch pen so I could place it at different points on the injector pump surface and tapped it while it turned over--nothing. I cracked the threaded cap 1/4 turn and fuel leaked out. I beat on it some more while the engine was cranking, then snugged up that cap again. Then when I turned the motor over, still nothing.

So what would any reasonable man do? Get a bigger hammer, right? So I got a three pound sledge, cracked the cap a 1/4 turn again, had the wife crank it, and proceeded to beat it pretty hard, and that finally did the trick! When I tightenned the cap again and turned the engine over, out same diesel. I hooked the fuel line back up to the middle injector, bled it out (which took a few minutes of cranking), and she started right up and is running like a top!

Thanks for the input, guys...and I'm pleased to report it's running perfectly!