Got a Delphi DP210 I am trying to solve here. Its quite a bit like a Lucas CAV mechanical governed with some extra emissions junk on it.
It always used to have a bad stutter or misfire coming off full load too fast. To me thats related to the timing advancing or retarding too far. Could live with that.
Last day of haying this year after a fillup it got such that it had less and less power, and would instantly stall with very hard restart if you suddenly reduced throttle setting. At same time turning the key off (solenoid stop only on the pump) caused a long run on before shut off instead of normal quick.
Checked filters and yup goop and water. Cleaned, primed, good flow to the pump inlet. Added atf and cleaner and have run the tractor 3-4 hours with little change despite no water.
Blew out lines to tank incase there was a restriction on the return but it seemed ok. Removed inlet connection on pump as there is supposed to be a screen but didn't find one.
The darned thing is a keyless pump so engine has to be put to TDC on #1 properly before you lock the shaft to take pump off so trying to figure out if it has to come off.
Delphi certified pump shop wants 2000$ to diagnose and minor overhaul on pump which I don't happen to have. Seems a bit steep given there are only about 200$ of things they replace.
I'm thinking the fuel delivery valve is the common part to the recent problem, the shutoff plunger I think is supposed to push that arm to 0 setting to shut off engine. The throttle linkage I think just pulls on the governor linkage which runs the valve. The boost diaphragm just moves to let fuel valve linkage travel farther under boost.
I just can't figure out why even just a small sudden reduction in throttle lever position causes an immediate hard stall that makes restart impossible for 5 mins.
Anyone ever work on these suckers?