Top speed on 84 Powerslot 351

[MooseMan]

Hi guys -

I'm looking at the reviews on the 1983 MasterCraft Prostar PowerSlot 351 from Powerboat Magazine (send me a note and I can email you a PDF). In it they are saying top speed for the boat is 45mph @ 4500/4600 RPMs.

I have the identical (1984) model to this boat and am barely breaking 40mph at the same RPMs. It now has a 14 x 18 OJ 4-blade - but I noticed no speed difference when I switched over from the 3 blade. RPMs still around 4400/4500.

Elevation is about 2000 ft higher than tested - and I have dropped jet size by two. Timing is about 8 degrees (a touch advanced over the recommended 6). Electronic ignition.

Any thoughts on this? Has anyone achieved 45mph out of this boat?

Thanks!

Don

[AR Footer]

I have an 85 with a 351 and a Powerslot with the original 3 blade prop and no changes to the engine and I get 44 mph at roughly 4400 - 4500 rpm.

[H20skeefreek]

I have an 85 with a 351 and a Powerslot with the original 3 blade prop and no changes to the engine and I get 44 mph at roughly 4400 - 4500 rpm.


I have the same boat. I'm seeing 43 at 4500-4600.

[ski_king]

I have an 82 with the same setup.
PCM 351, 240 hp
powerslot
14 x 18 prop

I get 45 out of it top end at 4500 rpm.
I calibrate the speedometers, so I know they are correct.

I believe my carb is still jetted as it came from the factory and I am mostly running my boat about 800 feet above sea level.

[JimN]

You probably won't see 45 at 2000 ft unless you can force more air and fuel into it. The other issue has to do with the water at that altitude. If you have too much power/torque, it will cavitate easier than at sea level.

[tph]

I have an '83. I switched to the 4 blade OJ a few years ago too. I think the boat lost a little top end with the new prop.