kubota d782 compression

[thomas57]

I got a used kubota mower with kuboda eng d782 compression is low 270 lb on all 3 cyl . after I put a little oil in each cyl it will go to 400 psi . are the rings bad or just stuck ? it only has about 1037 hours on the mower ,, but was sitting for a wile ( do not know long ) the oil that came out of it was like tar , it took 2 oil change to get oll out .

 

[hagrid]

Will it run? After 30 minutes at idle stuck rings might unstick. After that, if it's still down on compression I'd remove the head and check the bores for damage. If they're good you might consider a rebuild.

 

[85Hokie]

I take it the glow plugs are still out .....

place about 2 ounces of marvel mystery oil in each cylinder ........ let it sit ........
do it again the next day ....... and once more.

Then run another compression test ....... if it improves, they were stuck - if not, then time for rebuild.

 

[thomas57]

Will it run? After 30 minutes at idle stuck rings might unstick. After that, if it's still down on compression I'd remove the head and check the bores for damage. If they're good you might consider a rebuild.

yes it did run but ruff so I shut it off ,, both before and after oil change ,, got 3 new inj but did not put in yet

 

[lugbolt]

270 is low. I'm surprised it ran at all.

Pull it apart and see what's wrong.