1512D not running right

[jkratzwald]

I just inherited a model 1512. It had sat for a long time. I got it started and it runs well up until the engine gets good and warm. Then it loses power and dies. Won't restart until it cools off. If it were a carb'd engine, I'd swear it was a choke problem.

Fuel pump is good. New fuel lines. Bled the fuel system. Cooling system is flushed and clean. Even tried running it without the thermostat in case it was causing some kind of over heating.

I'm wondering if the valves could be out of adjustment. As far as I know, the engine has never been apart or worked on other than regular maintenance. I'm thinking that maybe once the engine gets warm, it effects how the valves seat.

Does this sound like a reasonable possibility? If so, does anyone know where I can find information on how to adjust the valves?

If you have other ideas of what you think the problem may be, please sound off. I'm out of ideas and don't know a whole lot about diesels.

Thanks in advance for any info you can provide. I'm hoping to make a good running tractor out of this thing.

 

[digger]

Jeff K.
If you would check the FAQ's you could answer your own question. It's amazing what you can find on this site if you take the time to snoop.
http://cubfaq.com/questions.html
95. How do adjust the valves on a D600 Kubota ?.

 

[bpientka]

Ok the 1512 has a return line for the fuel. Open the fuel tank up when it running and you should see fuel returning to the tank. If the returning fuel is very slow you may have a clogged intake screen in the fuel tank. The screen is on the pickup line not the return. You are just looking at the return to see that the engine is getting fuel. Mine acted very similar to yours it took time for the fuel to come back. Once it dies you can check the fuel line right after the fuel pump. Remove the fuel line from the filter (after the fuel pump) and turn the key on. You should hear the fuel pump running and fuel should come out the hose you removed. The screen is part of the fuel shut off valve under the gas tank.

 

[persoonj]

Jeff,1st thing I would suggest is running engine off of an alternate fuel source. Remove line from inlet of electric fuel pump and run a line into a container of fresh fuel. While warming the engine up monitor the upper and lower coolant hoses and the temp difference between upper and lower tanks of the radiator. Upper should be warmer than the lower. I would also remove the muffler, a plugged muffler can also create a overheat/hard start condition

 

[proessler]

Remove fuel tank, flush out all crud, change/replace all fuel lines, check screen @ petcocks, change both fuel filters add new diesel.

 

[jkratzwald]

Ok, I've done all of the fuel recommendations and none of it helped.

The engine gets warm under a load and quits running until it cools down. I let it sit at idle for at least 20 minutes and the temp stayed quite cool. I then engaged the deck to add load to the engine and the temp went up, but it still ran fine for another 10 minutes. I then started to drive it and temp quickly shot up and it died.

Maybe something isn't right in the transmission and it puts too much strain on the engine and makes it get too warm??

I looked through the FAQ and didn't see anything about how to check the trans. Any simple checks I can make on it? Anyone have any info on how the braking system works?

 

[jchamberlin]

Jeff, sorry to hear that the 1512 is still giving you trouble, perhaps Mr. Persoon will check back in: I understand he is quite the expert on Kubota diesels. As I compare your symptoms to what I have experienced on some of my gasoline twin engines, I would suspect the exhaust valve of sticking. This malady can be confirmed by either comparing a compression test when it is working to when it isn't working, or by gauging how fast the engine turns over; if the engine turns over quite well when it doesn't start compared to when it does start, then the valve (exhaust or intake) may be hanging up and the engine can't build compression, which takes force for the starter to overcome, allowing it to run more freely.

Just a thought, if you haven't already considered it.

If you find this condition (stuck valve), I would try --short term-- as many shots of aerosol Sea Foam as the engine will take (however you can access the exhaust valve stem), and longer term consider running Marvel Mystery Oil (MMO) in at least the fuel if not the oil (some people, my self included, are funny about what they'll add to the oil, and we're talking top cylinder lubricant anyway).

Again, hopefully Mr. Persoon will check back in with some helpful advice, I'm just trying to help aim an informed "shot in the dark."

 

[mhomrighausen]

Just .02 cents worth... There is a filter that is on the end of the fuel line that runs into the tank. My 782D had that critter plug up from sitting when I first got it. Your tansmission isn't the problem. Adjusting the valves isn't the problem. Contact one of THE BEST and MOST knowledgeable gentlemen on the Forum.... a.k.a. Myron Bounds. He has helped me countless times with my 782D problems. Your tractor is starving for fuel.

 

[bpientka]

When you say "the temperature shot up" how high are you talking on the gauge?

 

[dtanner]

If the diesel is starving for fuel that will cause a lean fuel to air mixture and that will cause more heat and not much power. I think you have a fuel problem. have you cleaned the filter in the tank.

 

[mhomrighausen]

Donald T. You're correct. Anytime a tractor has been sitting the fuel filters tend to get plugged and that fine internal screen is more than likely the cause. Plus... getting the tank thoroughly clenaed can be a bear. If not really clean that fine filter gets plugged quickly. Then the engine sputters and quits. Let the tractor sit and the fuel gets into the line and it will run like stated. BTDT.... Always check the simplest of things first. Like I've always stated... I may be lazy (depends on situation) however I am not necessarily stupid.

 

[jdiederichs]

Agree with the posts earlier, only to add that you must allow air into the tank. In order to draw fuel out air must enter or a vacuum will occur. When that happens the fuel pump will be unable to draw fuel. That is why the fuel tank cap must vent, if the vent is plugged that is the problem.

I would not worry about adjusting valve lash until you resolve the fuel starvation issue first, one problem at a time.

Have you actually pulled the shut-offs with screens from the tank? Those are the #1 problem for the diesel models. }

 

[jdiederichs]

Jim Diederichs, the thread killer?

 

[aschumacher]

Jim, you, a thread killer. Naw! Everybody probabily getting caught up on other things.
If you were to look around, I've killed a number of threads myself, but usually trivial stuff.

 

[proessler]

Go to my 4/29 response.... & Jim D's

 

[fcressman]

Curious if you ever found the problem. I'm wondering if it might even be as simple as thermostat stuck closed doubt if it's ever been looked at. Cooling systems rarely cause much problem so get ignored.

 

[jbrewer]

I found this necro thread, and I've done the fuel petcock filter clean several times. Looks like I'm due to do it again....sigh.

Off comes the seat fenders, etc...again! I usually find a glob of slime around the filter that's in the tank.

I wonder if there's a way to avoid this?

 

[dware]

Diesel fuel and plastic fuel tanks are subject build up of algae in the tank . This causes the fuel to jell and cause problems like you may have. I learned about this when a 50 hp tractor died in my driveway , had to call a service truck. Bottom line get some diesel fuel algacide to keep in your tractor / storage tank.

 

[Rgausman]

Need to verify if it is a fuel or mechanical problem.

Question When the engine will not start after it gets warm, does it crank over slower, faster or same as when cold? If the engine had been overheated in past, may be #2 or #3 piston scuffing the cylinder. Seen other Kubota engines do this...

You did replace the fuel filter after the electric pump - Correct?

The fuel shut on the bottom of the tank is a PIA. You can try blowing low pressure air (10-15 psi) from the electric pump back to the tank. See if the engine will run while it is warm. When the supply line is restricted you can tell the difference by the sound of the electric pump. Also look into the tank with the pump running, should see fuel returning back to the tank.