NJDave

I am convinced after doing my research that my HP500's are down on power and it is probably due to the weak or broken valve springs. I took the boat to Pro Roc marine in Brick township, NJ yesterday and they are going to due a leak down test just to make sure it is not something else. After talking to the guys there,they said that I am lucky to have gotten 315 hours with no problems and the springs should be replaced after 250 hours. They recommended replacing the roller rockers and lifters as well since there in there anyway.So I left the boat with them and should get it back next week end.

My question is what should I expect after the motors are freshened up? I was getting 95mph at 5050 rpm down from the original 5350rpm and 100 to 104 mph. I also put new Bravo 30p 4 blades labed props on the boat it only ran with non labed props at 100-104 standard 30p bravo 4 blades.


The guys at Pro Roc marine said after the refreshing of the motors they will water test it and if it consistently bumps the rev limiter they suggested removing the rev limiter to let the motors turn over the 5350 Limit and maybe turn 5500+. I asked what if I leave the water and the drives spin free out of the water? They said we can install an MSD soft touch rev limiter that can be adjusted with a chip change for any rpm desired. Any one here ever run there HP500's over the 5350 rev limiter? Is this going to kill the motors? I want reliability and do not want to rebuild the motors every winter.

cobra marty

The rev limiter will not keep your engine from over spinning when you leave the water. You need 32" props or change the drive ratios. Why not be satisfied with 102mph and 350hour reliability.