help with a L4310 starting problem

h10doc · Aug 16, 2006

A Friend has a L4310 while cutting with a finshing mower the tractor choked on a dirt mound and went dead. When she tried to restart the tractor it wont start. I checked it and got it running only buy a long cracking cycle with the throttle at max power. once its running it runs fine and no probles turn it off and to start it max power and a long start cycle engine hot are cold. Any thoughts on this? Is it the fuel pump weak are the injector pump bad? and how much is a injector pump? Thanks

rbargeron · Aug 18, 2006

Injector pumps rarely fail - it wouldn't start at all if the pump itself was bad. But there could be a problem in the linkage or internal governor. If the tractor stalled out trying to mow a sand pile, the last thing it tried to do was max out the injector pump stroke to maintain rpm. Maybe some linkage part just bent or slipped.

Once it is runing, does the governor seem to work? With the hand throttle lever in one spot does the engine maintain rpm under load?

h10doc · Aug 18, 2006

yes once its running every thing works fine no problems. the einge will also take all throttle changes just fine go from max power to idle and idle to max power and not miss a beat. So were is this internal gov. in the pump are engine?

rbargeron · Aug 19, 2006

The governor is forward of the injector pump, inside the engine. I don't have the shop manual for a L4310 - but I believe they are all similar. The governor automatically increases injector pump stroke so the engine goes constant speed even with changing load. An easy test to see if the governor is functioning is to drive on a road in high gear at constant throttle - as the tractor starts up a hill, you should hear the engine get louder and automatically give itself more fuel to maintain the same rpm. If it does not respond this way, the governor may be the problem. They have a couple small springs and levers inside - there's usually an access cover - one of the springs is for starting.

Another thing you can check on the outside of the engine is the fuel cutoff solenoid if it has one -

h10doc · Sep 7, 2006

found the problem cracked block with 420 hrs. on the tractor..

azhfl56 · Sep 7, 2006

Holy crap! Hope it is covered under warranty. Hard to believe that cracked engine block was caused by your description. Keep us posted.

dfkrug · Sep 7, 2006

h10doc said:
found the problem cracked block with 420 hrs. on the tractor..

So that resulted in low compression on one cylinder to give you the
hard starting? Anyway, that Yanmar 3TN84 engine is reliable....quite a
surprise about the cracked block.

h10doc · Sep 8, 2006

yep low comp. on one cycl. quite a surprize to me too. I never would have thought the block cracked with low hours and the tractor was maintained reg.