I am helping a friend rebuild/restore his M444. To pull the engine out we need to remove the pump from the crankshaft. We have taken out the bolts and nuts that hold the mounting plate and the high pressure line off the pump. The problem we are having is the pump will not release from the coupler. I am understandting that the pump and the coupler is a splined fit. My question is.....Is there any type of set screw in the pump/coupler spline fitting? We are using penatrating oil and lightly tapping on the pump with rubber hammer and wood block to hopefully release the pump from the coupler if it is only rust-held. Thanks for look'n. Engine is twin Onan. Tom