Water Pressure question? 300 promaxes
 

Hello all,

I just picked up my 28 powerplay with 300 promaxs and fleetmaster lowers this evening. The guy who tested the boat(who I trust) said the water pressure is about 6 psi at wide open throttle. Should I drill the holes out bigger on the lower unit? I dont want to lower the motors as the boat handles better at the current height. Thanks.

Re: Water Pressure question? 300 promaxes
 

I run the promaxs on my cat and I am at 9 to 10 psi at 4k RPM.And about 11 to 13 at WOT.My temps stay btween 150 to 160.Go to about 180 idling around but come right back down when I throttle up.What does the water look like comming out the pee hole?Mine is super strong even at idle.Try putting in a new impeller.About 15 minutes work.My pressure went up about 3 psi with new impeller.

Re: Water Pressure question? 300 promaxes
 

The water coming out the pee hole is super strong at idle. At 30 mph I only have 7 psi and it never goes up with speed. Any ideas?

Re: Water Pressure question? 300 promaxes
 

Mine was like that until new impellers.

Re: Water Pressure question? 300 promaxes
 

you may want to tap the top 2 holes on the water inlet of the case. you may be sucking airated water. test this theory using duct tape. wrap the tape all the way around the case covering a couple of the top holes.

good luck.