confused here...

[Bobby]

why is it that an old '82 Ski Nautique with a carburated 351 pulls so much harder and has a higher top speed than the newer '96 Sport Nautique with the GT-40 EFI motor rated at 310hp? My 96 Sport tops out at around 38mph, has a 4 blade prop - and it doesnt pull near as hard as my parents' 82 SN, which also has a 4 blade prop. I wouldn't think that the different weights of the boats would be too far off to make that big of a difference, but I could be wrong. Anyone know what's up? :?: :???:

[surroundsound64]

My first guess would be the prop. Then I would ask what is wrong with the 96. Then I would ask if the 82 has been modified.

Cool to have another Oklahoma guy here! I'm from Duncan, I moved to Tx this past August.

[M3Fan]

Less surface area on the old boats, less drag. Still to slow for the 96 though. What's the RPM at 38MPH? The RPM on the 96 at WOT will help us figure out the problem.

[Bobby]

ill check next time i go out. i'll also give it a tune up to see if it helps any.

[BigBald]

Are you running side by side and comparing? Could the speedometer be off in one of them? As far as pull....I would guess it's the prop. I know that the new prop in my 99 Sport made a big difference in the pull.

[bkhallpass]

350 lbs. difference in those boats, which is significant. However, you should still get at least 43 and probably 45 from that sport. As said, prop or tune up are likely issues. BKH

[82tique]

it's simple.....the '82 is the most bad *** nauti' ever made :grin:

[Rick]

The number of baldes the prop has doesn't matter, the pitch does. I would bet that the older boats prop is 1/2 inch bigger in diameter and 2" pitch less. The 96 is probably running a 12.5 X 15.5 and the 82 is probably running a 13X13 Check it out Good Luck

[Bobby]

it reads 4200 rpm at 38mph.

[83sn2001]

I believe WOT RPM on a GT-40 is around 4800. You may want to try a tune up and change the fuel filter for starters. My 83 pulls strong but it is no GT-40 even considering the bigger boat.

[dave210]

something is wrong with the sport top end will be close with the 82 but the gt 40 should pul hard out of the hole

[Roy]

I think you have the wrong prop, contact Acme or CC customer service, the GT-40 should see 4800 rpms, you are luging the engine.
Happy Boating!

[Mikeski]

Roy,

My initial reaction was the same but read on, he is only going 38mph so it's definately not overpropped. Something is not right with the motor.

[Bobby]

the prop on the sport is a 13 x 16. Also- there is a distinct gas smell from under the teak platform when it idles.

the '82 has a 13 x 13 prop and the dang thing will almost pull your arms off. I think it might just be a freak.

[Rick]

I'll bet with a 13X13 your 96 would top out at 4800 RPM and pull as hard as the 82 I have a 12.5X15.5 on my 2000SN with the MPI GT-40 and I'll bet I could pull 6 skiers up at once.