Problems with Lombardini engine

[Junior437t]

I have the Lombardini engine on my LT40. I am having some problems with it starting. When I start it the first thing of the morning it does fine. Heat the glow plug and crank a few seconds and it fires up. After it runs an hour or so and I shut down, that is when I have "restart" problems. When I crank for just a couple seconds  it will hit and run for a couple seconds and quit. Then it cranks 30 or 40 seconds to restart and before it starts I get puffs of black smoke out the exhaust and after it does start, get a good bit of black smoke for a few seconds. The engine has about 850 hours on it. Injectors were rebuilt less than 25 hours ago. Fresh fuel and filter.

[sparks]

The injectors were rebuilt but when they were installed was the injector timing set? There is a drip test on the injectors. Sounds like to much fuel draining from injectors. Do you have a lombardini service manual? If not email me and I'll get you one.   Thanks