I have a 95 merc 502 mag mpi. I've been trying to prime the oil system with my primer tool and drill. It will not prime itself, was, if I pull my filter off the inlet line into the filter with kind of pulse with air and alittle oil will come up, but barley anything... Any help??

make sure you did not connect the lines backwards.also,are you spinning the drill the correct direction.i only ask this because i don,t know you or how much knowledge you have.if you are holding the drill in your hand like a gun and looking at it from them backside the drill needs to turn clockwise.

is it a new pump?

drill spinning clockwise?

Got any more details on the engine? Recent rebuild? New oil pump? Why are you priming it now?

Haha yeah drill is spinning correct direction! Motor is a fresh rebuild never been fired up. Has the oil relocation bracket so the filter is up side down on top. I got the motor from a guy who just rebuilt it. Not sure about new pump, would have to look through his recites

And Ive been trying to find a picture of how all lines run to make sure they are right. But all the lines are pre bent so everything fit how it should have

did the builder prime the oil pump before he installed it.i hope it is something simple and not wrong size bearings or forgot to install gally plugs.

Did my 454 yesterday. Took forever, had an article (can't find right now) that said up to 20 minutes on bbc. Some wierd thing with some bbc's.
Mine took about 20-30 min before all rockers were flowing about 65+ deg. Outside.
Merry christmas and best of luck.

How much pressure should be on the shaft if you where spinning it by hand using the priming tool?