Yanmar 4TNV88 engine starts,then cuts out after 20-30seconds

Question edited for clarity.
Question moved from Cars and Trucks.

Free Service manual and the specs
https://www.yanmar.com/media/id/com/maintenance/catalog/100495.pdf


https://www.google.com/search?q=Yanmar+tf90-m+head+bolt+torque+spec

..

Question edited for a lot more clarity.
Question moved from Cars and Trucks to make model category.

Gator Diesel service manual Page 59

https://radionerds.com/images/4/4e/Technical_Manual_for_the_M-GATOR%281%29.pdf

https://www.google.com/search?q=John+Deere+Gator+6x4+with+Yanmar+Diesel+engine%2C+head+bolt+torque&

..

https://barringtondieselclub.co.za/yanmar/yanmar-4nte-94-98.html

https://barringtondieselclub.co.za/yanmar/yanmar-3jh-4jh.html

if the injector is held in by 2 bolts through a mount and the pipe is at the injector, remove the nuts , tap the side of the mount back and forth then use a pry bar under the mount and lift out of the hole
f there is a big nut under the injector that holds it in undo that nut and if the injector pipe is in the injector
tap and pry out
If the injector piper goes into the head and not the injector , remove it from the head first as it goes right into the injector body and acts like a grub screww

Check with manufacturer - could be a safety feature to prevent overturning the tractor.

The timing is controlled by the flywheel, it spins around and fires when the flywheel lines up with the coil it fires. White smoke may be an indication of a cracked piston ring. Hope this helps, plese post solved on fixya.com.So I get credit for a solved problem if it does. If not, check back and give me more info.

Contact Continental Engines Greenville SC, they maybe can help you. They are Yanmar dealer

My thought is that it is electrical, since it will not crank. I assume you mean that it will not turn over when you turn the key. I am not certain, but I think that if you have an electrical problem it may shut off the fuel supply as well. There is probably an electrical fuel stop on that machine. Since there is no spark plugs or electrical system to make the engine run, by shorting out the electrical system it will not stop the engine.

you say the engine shuts down when it gets hot if it runs rough before doing so it could be the coolant temperature sensor allowing the engine to  overfuel  if the engine cuts out in a couple of seconds but sounds smooth it could be the fuel pump , if it cuts out instantly its electrical.