If you look at the front of the Milodon oil pump, you can see the blue cap on the unused second oil intake. I had no luck pulling a prime with this pump and suspect the capped port has a lot to do with it. The port is about four inch from the cap end to the opening for the pump gears. Thats a lot of dead air filled space. I cut a 5/8 diameter bolt up to fill that four inchs. I hope it cures the no prime problem.