So I rebuilt the engine. New rings,con rod bearings, carb, electric system and gauges. This will be the 8th time dropping the oil pan so I'm really hoping to avoid it. As it goes I had the tractor running for about 3-4 hours 3 weeks ago. I had relatively low oil pressure 10-15 lbs hot. This tractor sat for roughly 35 years outside. I put a new oil gauge and a new oil puck up line because the old one was loose. I also took the pump off for inspection but all gears were tight so I put it back on. Now I have no oil pressure at all. Disconnected lines and took out filter and still nothing. Any ideas to fix?