97 225 Promax More RPM

[Vegas86]

I have got a lot of good info. from all of you I am hoping for some more help.I have a good build on my motor, steel cage brgs. heads done 150 + compression ,oil injection removed etc ,about 50 hrs. on it . I had my ECU worked on to turn the limiter up to 7.5K (Dennis Hoffman) great guy to talk with,I cannot seem to get to the 7500 rpm is there something else I need to do ? I have tried smaller prop not much change currently running 30 Hoss Triton also have a 28 Triton 28 Pro ET 30 Pro ET do I need to go smaller ? I have verified WOT so whats up ? The motor pulls strong up to about 6200 & then just kind of flattens out might hit 6500 if I play with the jack plate some any help would be greatly appreciated Thanks

[Merc 2.5]

It would take a very lite boat to spin a 30 to 7500. Get u a 26. , still liable not reach that 7500. What kinda boat?

[Vegas86]

Hydrostream HST 1986

[eli]

Might do a leak down probably find your answer

[Merc 2.5]

I know sumone around here has one or had one with promax , curious to hear prop and rpm they ran theirs?

[KIRCHNER]

It would take a very lite boat to spin a 30 to 7500. Get u a 26. , still liable not reach that 7500. What kinda boat?

Agree, that prop way to big. i cant hit 7500 with a 26, wish i could. 225 pmax.

[Merc 2.5]

Agree, that prop way to big. i cant hit 7500 with a 26, wish i could. 225 pmax.

How much do those hst weight??? my bassboat quite bit heavier I'd expect, but I can get 6400ish with 26 , It would need weight around 5 or 600lbs to get that kinda rpm from a 28 or 30?? Theres a guy on here had a built promax on a ally and turned 26 to 7700 with 1.62 , but again its light.

[Vegas86]

Weight 825 roughly with half tank fuel rigged no motor. Weighed it on my crane at work before I put the motor on . Sounds like I need to try a 26 see what happens? I will look for one any suggestions on make . The Hoss props I have seem to work good what you guys think?

[Merc 2.5]

I think 26 hoss b great starting point. I figured simone with a hst would had already chimed in by now

[SSTOM]

I dont have a HST but i have a 225 Promax i run on my Allison SS standard weight hull. My promax is stock porting has 150psi compression,metal caged bearings, vertex pistions, sps rod bolts and a 16 amp charging system and a recurved ecu with a 8500 limiter. I can spin a 26 to 8100,8200rpm a 28 will turn 7800,7900 with 1.87 gears never had a 30 on there. the Promax is a good little powerhouse.

[Vegas86]

Good info thanks my motor is basically the same as yours I just didn't list all but I still have the 40 amp charging same 1.87 Gears . Your boat is a lot lighter than mine but gives me a good starting point.

[Capt.Insane-o]

Hydrostream HST 1986

How soggy is it? The HST wasn't available in public form until 88

[Vegas86]

Sorry Capt.my Vegas is 86 my HST is 89 I think the core is all good I have a bore scope camera went all up in there everything was dry from what I saw, it has full interior & factory floor all original been stored in garage all its life I sealed the top & hull together several years ago.Never any leaks ?