1stfntn

Also posted in the prop section but wanted some Fountain owner input. Hopefully someone else has been down this road B4.

The current setup:
2000 38' Fountain twin step (the small steps); Twin 500HP Carbs with about 490 - 500HP each at the prop (20 - 30 over stock); Bravo I drives (not XR's) with non-labbed 26P 4 blade Hydros turning IN; 5350 RPM (i.e. stock rev limiter) @ 75 - 80 mph depending on passengers, load and conditions; most recent run 5350 RPM @75 with 6 people and two full tanks of gas (260 gallons total) on 95 degree day with high humidity.

Boat seems to like a lot of trim to get the max mph; usually there's a good 5+ mph in just trimming the drives from flat to "5" on the trim indicators at WOT.

Question is what prop work to do or what prop to switch to for better top end performance while still maintaining reasonable cruise and hole shot (I know both will be compromised to some extent if I go up in pitch).

Options I see are:
Upgrading the ignition, raising the rev limiter and turning the 26's faster (maybe 5,600 RPM), possibly having them labbed and reworked to hit the 5,600; Trying 4 blade 27's or 28's in Bravo's or Hydro's and possibly having them labbed as necessary; Trying 5 blade 25's or 26's (probably Hydro's) and possibly having them labbed. Any other thoughts???? Have considered sportmaster lowers and/or shorties as well. Would appreciate ANY input.

Thanks in advance,
Brad

32Fever97

I would try a set of 27 or 28 hydros. I am running the same engines, and I think that 5600 rpms is way too high (anyone agree?) I have a set of 27s and have run a best of 88 mph. I think that you could step up, however time to plane will increase.

1stfntn

Thanks for the reply 32Fever97. I really appreciate it. I am going to try a pair of 27's and 28's after I get my final carb and ignition tuning done.

I agree on the 5600 RPM; I really don't want to twist the motors that tight if I can avoid it. However, I think my new cam likes to rev more than the stocker and a few people have said peak HP in a stock HP 500 doesn't happen until 5,200 RPM, so it was just a thought. Probably not the way to go.

88 mph in a 32', now that's got to be fun. Had a friend in Austin who was running almost 90 mph as well in his 32' before he sold it. Wild ride!!