jessie00721
New member
Hello, I am trying to put together a 90's style mercury 150 efi engine and trying to figure out how the oil pump lines should be routed. This unit has a mechanical oil pump. I know I could just bypass it and just premix the gas but it works and was going to just hook it up the way it was designed. I am confused on where the oil line out of the pump should go to. My manual said that early 90's carb and efi output from the oil pump connected right to the main fuel line coming in. I have seen a carb model do this by putting a t fitting connecting the oil pump output and fuel line. I dont think this is ideal for the efi cause the engine would need to be running in order to get oil mixed with the fuel, so everytime you pump the ball for your gas tank you get unmixed fuel going right over to the water seperator and directly to your fuel management system. Maybe this is how it was supposed to work? I dont know. I also had a another manaul which pics was not clear but it appears at the bottom of the fuel vapor tank there was a check valve and it kinda looked like the output of the oil pump was connected there, I dont know if that is a better setup or if it is right or not. I had an identical engine of this before but cant remember how the lines where routed. Any insight on how to properly hook up the oil line would be great. A flow chart or detailed instructions? Pics? Thanks for any help!
Jessie00721
Jessie00721
