850 Won't Start

[Republic of Texas]

Troubles begin:

I was out shredding 2 weeks ago when I let the radiator clog up with debris and the tractor over heated. Left it in the pasture for the night. Next morning I returned, filled it full of coolant and it fired right up. I drove it straight to the house, let it cool down, then proceeded to spray out the radiator with the water hose.

Once the radiator was nice and clean, I attempted to start the tractor. Clunk! Clunk! The starter engages but does not turn the flywheel. I inspect wiring and what-not, and find that the battery (had both top posts and side posts) made contact with the frame on both + and - posts. It was making a frying sound along with melting some plastic on the battery and a little smoke. Not good.

Mechanic buddy said it's the starter. I get a new starter and put it on with questionable battery. Same symptoms. Clunk! Clunk when I turn the key. My thinking was that the old starter is good, it's the battery that's bad. So, I return the new starter to Oreilly's and get a new battery instead. Put on the new battery, same thing: Clunk! Clunk!

Measured voltage to starter with key engaged, 8v. I read on here that the starter needs at least 9v to turn the motor. Short of rewiring the whole tractor, I added a start relay. Same Clunk Clunk.

I decide to jump the starter solenoid with a piece of wire (tired of climbing on/off tractor) so I can stand by the motor and look/listen better. Same clunk naturally. I keep touching the wire to the starter (pissed off) and the motor turns over for a second!!! Great! Hit the wire to the starter again, clunk! Except this time, fuel spits out from around the injector closest to the motor....... no clue here.

As I am rethinking my situation, I notice the compression adjuster on the top of the motor and so I pull it back to lessen the compression. Motor spins over!! But now, fuel spits out of the smoke stack! I put the compression adjustment back where it should be. Fuel spits out around the injector again.

I'm at my wit's end. At this point it's probably something extremely simple but I can't think of it (not a diesel mechanic). Is it the starter?

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I can add pictures or videos if someone thinks it will help diagnose the problem.

 

[beenthere]

:welcome: to the forum.
Doesn't sound good, but hopefully there will be a simple and happy ending (as you suggest).

Sounds like the trouble started when you sprayed it down with water to clean, as the tractor started in the field after adding coolant.
Then too, maybe something other than debris in the radiator caused it to overheat...head gasket? piston? ??

 

[Republic of Texas]

How can I verify that a head gasket or piston is bad without dismantling the motor?

 

[Republic of Texas]

Can anyone add anything? I have no one to ask who won't charge me $65+ an hour. Can someone please help?

 

[beenthere]

You mentioned a "mechanic buddy". Does he charge $65?

If working on it yourself, then getting a copy of the tech (service) manual would be first priority, IMO.

But things may be serious enough, that bucking up to hiring it done may be in order here.

Can you tell us more about your situation? Experience yourself, as well as more history of this tractor. Tools you have available, and anything else that will give us an idea how to give you direction.

 

[AGGIE00]

That little yanmar is about as simple as it gets. Had the same thing happen to my dad's many years ago and replaced the head gasket. It only takes an hour or so to replace.

 

[Republic of Texas]

Ok, so if I'm understanding correctly, it is in fact water/coolant leaking inside the head. This is most likely due to overheating wearing down the head gasket? Perhaps age as well...?

I will order a head gasket and go from there. I will post back when I replace the head gasket. I really appreciate the advice!!

Note* - Mechanic buddy doesn't charge me, but he's not 100% certain what it is and we both ran out of ideas. I can do the work, but diagnosing problems isn't my specialty.

 

[Republic of Texas]

I appreciate the replies. I will be working on the tractor this weekend. Will post pictures and/or video. Again, I can't thank y'all enough!!!

 

[Republic of Texas]

I have verified that it is coolant coming out of the exhaust. I pulled the compression adjustment and spun the motor over until the water appeared to stop coming out. Then I put the compression adjustment back to normal and spun the motor again.

This time, the motor turns over and tries to start. No more clunking/locking up. At this point, I do believe that the head gasket was blown when I let the motor overheat. I have ordered a head gasket from the dealership and it will be here next week.

Question: I read about needing to have exact torque on head bolts. What all should I replace after I take off the head? I've never worked on a tractor before, so if someone could just point out a few things to look for and double check, I would be highly appreciative.

Any additional advice will be greatly received. Thank GOD for this forum!

 

[Mechanos]

I have verified that it is coolant coming out of the exhaust. I pulled the compression adjustment and spun the motor over until the water appeared to stop coming out. Then I put the compression adjustment back to normal and spun the motor again.

This time, the motor turns over and tries to start. No more clunking/locking up. At this point, I do believe that the head gasket was blown when I let the motor overheat. I have ordered a head gasket from the dealership and it will be here next week.

Question: I read about needing to have exact torque on head bolts. What all should I replace after I take off the head? I've never worked on a tractor before, so if someone could just point out a few things to look for and double check, I would be highly appreciative.

Any additional advice will be greatly received. Thank GOD for this forum!

I hate to say it, but I've never heard of a head gasket just "blowing" because of an overheat. I am more suspicious of a warped or cracked head or a cracked block. I certainly hope I'm wrong, though.