50 HP Mercury Power Trim

[Chuck Larsen]

I was given my father's old fishing boat and it has a 50 HP Power Trim motor on it and I think it's an early 1980's model. It hadn't run for a while so the carbs were pretty well messed up. I took it to a Mercury dealer (who wasn't really wanting to work on that old of a motor) who cleaned the carbs and put in new kits. I took the boat home and it would run until it ran out of fuel (what was pumped up by the bulb) and then it would die. I took the boat back last week and they cleaned the carbs and replaced the old fuel lines. While in the shop the boat will run on their shop fuel tank...only if the tank is elevated to a level equal to the top of the motor. If the tank is lowered inside the boat the motor will eventually run out of fuel. So here's what has been done so far in their shop:

New Carb kits (first visit).
New fuel lines (second visit)
used my fuel tank and thiers to test motor (second visit...still won't run)
New primer bulb (second visit)
Now they plan on putting in a new set of carborator kits in case they have a bad diaphragm...if that doesn't work they say I can take the boat home...they won't work on it anymore.
Do you have any ideas what could be wrong. The motor runs great when it's getting fuel.

Thanks

[boats.net]

duplicate thread