Something is out of whack. I've set up numerous Heats with similar power and they all ran low 70's on GPS at around 5100-5200RPM with stock 26" B1 props , 1" drive spacers and 1.5:1 drive ratio. I'd get a digital tach and verify accuracy. Check the gear ratio on your drive. The numbers work out about right for a 1.65:1 gear ratio.

Bob

5 Blades = about $200 per Blade

Yasser, but since your's is now a "demo", maybe you can save a little $$.......

I agree with Bob.. The gear ratio's are changed in the lowers on the XR drives.. the math works out to about 16% slip with the 28 bravo prop and a 1.65 gear ratio. That makes more sense... What then doesn't make sense is that the 27 P5x with no spacer.. doing the math with a 1.65 ratio gear.. equals 7% slip. I have never seen a P5x on a Heat with slip numbers that low... spacer or not.

Something really funky is going on here. I would check your tach for sure, along with verifying your GPS speeds again, and your drive ratio.

Chris

Surely the tach isn't wrong? I hit the rev limiter with the B1 28 with no spacer and the old gauges. I will check though. I'm also gonna take the lower off and check the gears today? Can I pull it apart myself or do I need to take it to my mechanic? So if all is right, I guess it's time to unass some money and find a p5-x? Next thursday it's gonna be setting on a lift 2 hours away, so i gotta try to get it right before then. Hope you guys can help.....

Derek

Guys,
I think 1:65 gears in a Sportmaster is unlikely. I just checked the specs for a 525 with XR and Sportmaster housings, and they are only offered in 1.26, 1.35, and 1.5 ratios. Someone could have have changed the gears out, but that seems unlikely too. Maybe that's a question for the guy you bought your engine and drive from.
Derek, I think you have a bad case of propeller slip, and/or bad information from one of your gauges.
Regards,
Steve

Anyone try a bigger diameter prop? My Prop guy mentioned a maximus? my 496 would smoke this all the way to the top and its killing me!! LOL

Derek

Just curious, is this the only Heat running a Sportsmaster lower?
I have heard some stories on these and they weren't exactly good ones. Only hearsay though.
Dou you happen to have access to a standard lower that you could try?
Dave

The only guy I know of running a sportsmaster lower on a Heat, was the 1st guy with a 600sci on his boat, who lives near St George Utah. He could only get the boat going 78 mph. He tried spacers, props, etc. I on the other hand had an IMCO lower and when I put a spacer on, along with a 28 Bravo, hit 80-81 mph with my open bow boat, which is supposed to be about 2 mph slower than the closed bow boats. I could hit the same speed with a 28 or a 30, just different RPM's.

I think there might be something to trying a different lower unit.

Chris

Guess I'm swapping the sportmaster with a brand new (Very Low Hour) XR off a Shockwave I have. Gonna start with a B1 28 and take a few others (B1 26 and a B1 32) that I have. The sportmaster was 4 3/8 below keel with the 1" spacer and this one is about 3 3/8 (I think). I will measure tomm for sure!! Hope this works..



Her's what I took Off...

Here's What's Going on..

Halfway there!!!

There it is!! Finally Something that someone knows about!! Guess we will start all over Going to the Lake in the morn with a huge smile and a good attitude!! LOL!! Let me know if you guys think this was a good move... It didn't take long so its not that big of a deal...

Derek