Mitsubishi K3H problems.

[sheepgrower1]

Hello, I have a Mitsubishi K3H 3 cylinder diesel running the sawmill. A great wee motor however when starting up it revs to valve bounce and when idling will rev up and down before settling down to normal idle speed again. Under load it will also rev up and down but not to valve bounce. There is no air in the fuel and all the fuel lines are good so according to me its either the pump or most likely the governors of which I hold little desire to tear apart, it a diesel mechanics job. We want it to run at 2400 rpm. Any clues most welcome.

 

[Dave M7040]

Hello, I have a Mitsubishi K3H 3 cylinder diesel running the sawmill. A great wee motor however when starting up it revs to valve bounce and when idling will rev up and down before settling down to normal idle speed again. Under load it will also rev up and down but not to valve bounce. There is no air in the fuel and all the fuel lines are good so according to me its either the pump or most likely the governors of which I hold little desire to tear apart, it a diesel mechanics job. We want it to run at 2400 rpm. Any clues most welcome.

Suggest you contact forum member Piloon who is a bit of a Mitsu expert.
http://www.tractorbynet.com/forums/members/piloon.html

It may be necessary to remove the injection pump and take it to a diesel repair and rebuild place. My caution and hence the suggestion to contact Piloon, is that you don't want to loose the injection timing. Like ignition timing in a gas engine.
Dave M7040

 

[sheepgrower1]

Suggest you contact forum member Piloon who is a bit of a Mitsu expert.
http://www.tractorbynet.com/forums/members/piloon.html

It may be necessary to remove the injection pump and take it to a diesel repair and rebuild place. My caution and hence the suggestion to contact Piloon, is that you don't want to loose the injection timing. Like ignition timing in a gas engine.
Dave M7040

Hello, we fixed it this afternoon with some online help. It has been the fuel filter housing that was leaking air, it was faulty and the only way we could find it (after trying just about everything else) was to take it off, block both hoses and hand pump it in a bucket of diesel, there were the smallest of air bubbles appearing under the plunger so it was thrown out and replaced with a new set up. So far so good but it will need running for an hour or so to get the last of the air out of the whole system. I think I have attached the old anew set up.

 

[sheepgrower1]

To my great relief today we found the main problem with this engine, the flyweight bolts had fallen out. No idea how it came to happen but one of the weights was on the wrong side of the slider too. Shes all fixed after 3-4 years of on and off trouble

 

[thepumpguysc]

WOW>> THAT IS an odd problem..
just by the description I knew it was a governor issue, but not something I was willing to "talk" someone thru.
Even getting the front cover off can be a nitemare.. let alone working w/ springs flyweight & adjustments..
SO GLAD you found & fixed your problem.. it could have been BAD..

 

[sheepgrower1]

Its been unheard. I showed the diesel mechanic here and he said it could have been like that from new by not being assembled correctly thereby with it out of balance caused the bolts to vibrate out, or after they had fallen out then then flyweight shot off the end of the shaft on full throttle, either way we will never know. Its done little hours and that problem is obviously why the engine was replaced, it had a triple belt set up on the end of it with 21mm belts driving a water pump/air compressor/generator? The end seal we replaced while in there, its the same as a Mitsubishi camshaft seal if anyone needs one, the old one was still like new hence the belief its done little work. Shes going like a rocket!

 

[PILOON]

Hi from the expert LOL, ???
OK, I have Mitsu tractor but have never played with my K3 engine other than change fluids.

Interesting as I once had a front differential problem whereby all the bolts that held the crown gear in place had sheared or simply fallen out.
My cure was to drill bolt heads and safety wire them as well as to use Locktite.
They have not moved since then, (some other TBN members also suffered that same problem.)

Those Mitsubishi engins are one tough engine!

 

[sheepgrower1]

The oil pressure seems a bit high to me.

 

[sheepgrower1]

I saw a Case 870 tractor that was sold new, the fellas in the factory never bent the crown wheel tabs over and it fell off.

 

[sheepgrower1]

Here is the old end seal, NOK AH20571, the new one had a U after it. How many hours does everyone reckon this one has done, to the nearest say 1,000 hours, its still in good order.

 

[sheepgrower1]

Here is the old end seal, NOK AH20571, the new one had a U after it. How many hours does everyone reckon this one has done, to the nearest say 1,000 hours, its still in good order. View attachment 559177