2 cyl. Kubota injection timing

I have a Kubota ZB600 diesel engine and the
manual calls for 21-25 degrees before TDC.
We recently rebuilt it and we checked the
timing and it was about 13 degrees before
TDC. We took out the two shims that were
under the little injection pump and it is
now about 16 degrees BTDC. There are no
more shims to take out. How do I move the
timing more? As a side question, the engine
is rated at 3200 rpm, but we only run it at
about 3000 rpm. Does reducing the speed
negate some of the timing advance? In other
words, is 16 degrees now sufficient?
 
How are you timing the pump?? Depth mic?? spill timing?
If it has an electric shut off, it has to be energized..
Did you get the block or head "shaved"?? {decked/straightened}
..recheck your procedure..
 
I'm with the pumpguy, HOW was timing checked? Spill timing is best, but must be done carefully. Also be aware if the pump has retard start plungers timing WILL spill flow later IF the rack is full on.
 
Thanks for the replies. The head may have been resurfaced way back when we had hardened valve seats put in it. But, the uinjection pump bolts on to the engine away from the head. The way we checked the timing was to hold the governor wide open and slowly turn the engine over by hand with the fuel lines off the pump, watching for the first tiny bit of fuel to ooze from the pump. We then compared that to the mark on the flywheel cover and flywheel.
 
If I remember correctly, spill timing measures beginning of delivery. This occurs when the fill port in the plunger closes, not opens. In other words you would need to continue turning the engine until fuel stops coming out of the port. Usually the fuel inlet of the pump is pressurized so the actual port closing can be observed. I would bet when you use this method, you'll find that the shims will have to go back in.
 
Thank you for the reply. Sounds like I am doing spill timing. The problem seems to be that the timing is too retarded still. The "spill" is starting at 16 degrees BTDC and continues after that. I am trying to advance the timing but have run out of shims to remove. Please advise.
 

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