What size line/hose do you have on the dump port of the pressure relief valve?

Does your drive have low water pick ups also ? Some drives have both side and low pickups.And what speed does your Warlock go ?

Do you have the thermostat spacer and thermostat installed/orientated correctly ? Many people mess this up without knowing.

Lastly, it's payupsuckers fault. :)

It's the new-style Merc thermostat housing.

My 502 MPI does the same thing, and has done it, per the previous owner, since the motors were put in the boat years ago. It shouldn't be a problem, but if you want to release some of the pressure, do like everyone else has said and plumb the rear of the intake with a -4 AN or 1/4" fitting and hose.

3/4 i think.thats the size of the outlet

pick ups are on the side of the lower unit only.no thermostate spacer and i believe it is installed right.spring is toward the botton of intake.boat dose 80 mph at wot.