Need advice please
 

I have 2000 27' Fountain Fever 502 MPI with roller rockers, lightning headers,MSD ignition, Arizona speed and marine computer and flame arester. The prop is hydromotive 23 pitch. Why is my GPS speed 67.8?

well that's about all you'll get with a 23" prop. What rpm's are you turning? Are you hitting the rev limiter?

The WOT RPM IS 5300. I am not hitting the rev limiter

That's about 12% slip. A tad on the high side. But not too much. I don't know too much about the 2000 hull, but I know that the later 27's equipped with 496 HO's got about the same speed as you are. Except they used a 1.65 gear ratio with a 28" prop. 496HO's make 425hp and I think the old 502's were around 415hp stock. I really don't think anything is "wrong".I would say the next step if you're looking for more speed is the outdrive height. (X dimension) Set the drive to neutral trim and find out the difference in height between your propshaft and the bottom of the boat. My shaft sits 1.5 inches below the bottom. That's fairly aggressive. Going with a shorty and re-propping MIGHT be a path for you.

I have a stock HO in my 01'. The best speedo # I have seen is 71 mph and 4950rpms-ish turning my bravo 1 26RH 1.50. Normal top speed on speedo is 68-69 and 4900 rpms. THe previous owner said he gps'ed it and ran 71.5 mph....not sure as to the validity. My prop shaft sits about 1.5 inches from the bottom too. Prop slip is around 15% i think. I think you should get another prop....labbed b1.

Remember our Bravo 26's are really 25's. So your propslip if all is well should be around 9%. I'm told that if you can crack 70 with a 27, that's doing pretty good.

I would like to thank EVERYONE who "chimed" in to lend advice on my situation. I will eventually get a Labbed prop I must say right now I am getting EXCEPTIONAL gas milage I guess that is the sacrifice for going faster. Unsane how fast is that 29 with the 525. Once again thanks for your time.

Right now I'm still playing with a 5 blade and have run into the rev limiter (alarm is at 5400) at 77.9mph a couple of weeks ago. That was with 60gal of fuel on board and the prop was slipping big time. Throttle up cupped it some more but I haven't done any real running with it yet. On my 26" Bravo, on a light fuel load, about 1/3 of a tank, I hit 77.6 at 5350 on the tach over in Clearwater. Last winter up in Jax, on my 28" Bravo, I put the boat into chinewalk and that happens right at 80 on that hull. I backed it off on that run. This upcoming winter I will play with some labbed Hydros or even one of their CNC's. I hope to see 82 or 83 in perfect conditions this winter.

Also, be careful with labbed props, they are only about 1/12 as strong as a regular wheel. If you hit something, it is most likely wasted. Keep a spare and double check your X dimension. Raising it will free up that power more, it will just be a pain to plane out at times.

UNSANE, what do you suppose the 29 w/ 600sci runs? Just drives through the chine walk in the upper 70's that you experience?

Probably about an easy 85. Yes, I'm told that just countersteer the walk and it will settle down then you can open it up. The chine walk comes on all of the sudden. I have GPS'd 78.5 before and there was no hint of walk. The one time I touched 80, she started dancing. The thing is, that was my second time with the boat so I backed off.