My Kubota M6800 has 3600 hours on it and it started shutting off back in the summer randomly and I assumed it was an electrical issue because it would always start back up easily, never smoked or knocked. The problem got worse so I changed the Fuel cut-off solenoid to no avail and then changed the oil pressure switch with no effect Then I put an oil pressure tester on it and there was basically no oil pressure, when I took off the tester and left that orifice open the oil would come out in a slow stream only. After I checked the relief valve and the oil suction screen I went into the gear case and found the issue, but created more concern. On the plate on the back of the oil pump there are 8 screws that basically hold the pump together. Well, mine only had five screws in it and 2 of those were loose. So, I'm assuming that is what created my lack of oil pressure problem, now my concern is what happened to those missing screws. I've searched all over that engine for them. There's no scratches/gouges anywhere in the engine like you would expect if some screws/bolts were loose in the gear case. I had already changed the oil since the issue started and there's no metal pieces or flakes in the current oil that was in it. I've got the oil pan off and have looked all over the bottom of the engine and there's just no sign of these screws. Anybody have any input on how they would proceed?