Gear ratio for 38' Fountain
 

38' 2000 Fountain Lightning,700 hps 1.36 gear ratio. 85 mph @ 5000 rpm 28 pitch Bravo 1 props. I have a chance to change gear ratio's since I blew one up and the other is about to go. Ive been told to change back to a 1.50 and figure out why its so slowwww. Any input will be appreciated. I've been told by many that this package should be turning mid 90s at 5500. I am willing to change props as well to make my package work to it's full potential.

fixx
 

the drives wont be as strong as the 1.36 ratio,,the boat will accelerate to speed faster with the 1.50 ratio gears.. i would rather have the dtronger gears,,you could always change the blower pully and reflash to acheve your mph..

I believe the original set up would have been Bravo's w/1.50s from Fountain? These are IMCO SCs, the shop that is working on it told me this used set must have came from a cat?? I can only afford to do this one time and get it right. Does any of the blade suppliers or Fountain owners have some input on a boat like mine running 700s, what cocktail would be perfect?

each pitch is 200rpm. 28pitch is to big, you need to go smaller . that will bring the rpm up you will gain more top speed , i put a 136drive on my baja with 718ponys i run a 25 mirage top speed is 78.6mph at 5100. my motor dyno at 5800. i put a 23mirage and turn it 5700rpm doing 85.i try a 26pitch did 75 at 4900 way to big of a prop now i run a 23 pitch .at 40mph i go wot and race a super charge wave runner that does 70mph i blow them away so smaller prop gave me crazy speed from 40 on up :drink: http://www.youtube.com/user/SuperBaj.../2/jmnD9VV_jB0

My 1998 38 Fever ran 92mph with t700 hp , 28 true pitch bravo ones by bblades & 1'' short imco lower.
1.50.1 ratio
Drop down to 27 pitch & let her eat !

Had been told the only reason to step up to 1.36 gears is if you run out of prop. In the earlier years before custom prop manufactures, if your boat needed more than 36 pitch props, no one made them. Now with the ability to make props with much larger pitch, not so much an issue. My 38/700 Fountain is running 39 pitch Herings with 1.5 gears.
I think you would be happier with 1.5 gears.

you didn,t specify if you have regular bravo or xr drive.if it is an xr,the change in ratio is in the lower gear set,all xr uppers are the same ratio.if you have 700hp,you should be able to spin a 26 pitch prop to 5500 rpm[or close to that],remember,you prop bigger when you have the power to spin the bigger prop.when i say 5500 with a 26 p prop,i mean with 1.36 gears.when you say 700 hp,is that dyno verified or app hp numbers?

Beak Boater
 

With your larger steps and staggered set up what kind of speed are you getting out of it running...39's wow. Six. five or four blades?

mike tkach
 

Have the original build sheets from Teague from previous owner so I believe them to be true 700s. The drives are IMCO sc's. Called Teague and they told me I should be running it at 5600-5700 and they too said I needed lower pitch. Now that the drives are gone, I thought this was the time to switch gear ratio's as well if that is the right thing to do. Need new props anyway. Trying to get as much experienced info. before I dive into this rebuild.

Six blade Herings, at 5250 rpm 114 mph.