Motor height and prop slip

[Jwilb88]

I have been tinkering with my set up the last three weekends and here is what I have ran:

1st weekend- motor set and 1/2" below pad, boat ran 70mph at 6100 rpm
2nd weekend- motor 1" above pad, 71 mph @6300 rpm
3rd weekend- motor 1 1/2" above pad, 73 mph @ 7,000 rpm

Boat ran all three weekends with a 26 chopper with 15-20 lbs of water pressure boat is a 91 virage with a 2.5 150 merc. I know it needs more power but I refuse to re power before I re core so a new motor is out of the question until next summer.. The boat handled better at high speed with the motor @ 1 1/2" above the pad, but the prop slip numbers are terrible. Why are the slip numbers so high is my question? Is the prop junk or is the motor too high?

[Mr. Demeanor]

Dont worry about prop slip. Its a very subjective number. Your ran faster and handled better and thats what matters.
I would try 1/4" increments though. You might go down 1/4" and see how she goes. 1/2" is a big jump.

[Jwilb88]

Thanks for the input I'll set it at 1 1/4" and see how it does..

[transomstand]

Stock Choppers need help when run that high, they lose bite, need to add some cup. Bet your holeshot is going away too as you raise it.

[Jwilb88]

Transomstand your absolutely right the higher the prop height the worse the holeshot gets. I let it back down to 1" above because that's seems to be the happy medium for now.. The sacrificed hole shot isn't worth the added 1,000 rpm and 2mph top end. I'm gonna call tillmans today and see if he can work my prop and have it done by July 4th

[Dave Strong]

Could you go 1. 25"? Might like it.

Dave

[Jwilb88]

Dave that''s what I'm gonna try this weekend and see how it acts

[gem56]

Sounds like you need a prop guy to help ,From what you have said maybe modify the chopper by increase cup or spoon , this will lower
revs and increase speed by holding the water on the blade surface longer

Russell ( former prop shop owner Queensland Australia )

[rkmirage]

If it needs a re core then don't push it any faster until you get that done. If the hull is flexing then it won't go much over 70 anyway. With a spongy bottom they hit a wall around 70 and setup won't help much. Been there, done that!

[Schramer]

If it needs a re core then don't push it any faster until you get that done. If the hull is flexing then it won't go much over 70 anyway. With a spongy bottom they hit a wall around 70 and setup won't help much. Been there, done that!

Agreed...just put at 1 1/4" and enjoy for the summer! Also keep an eye on the hull and transom for stress cracks and if they start to appear.....pull the plug!

[Jwilb88]

Agreed...just put at 1 1/4" and enjoy for the summer! Also keep an eye on the hull and transom for stress cracks and if they start to appear.....pull the plug!

Will do! Thanks for input guys! Hopefully next year I'll be able to show you guys my freshened up virage with some BIG POWER out back!

[David]

With only 150 HP, setback helps carry the bow, or a prop with more bowlift, or both.

When I had a 150 on a Virage, with a Land and Sea jackplate, my 26 Hoss Hyperdrive was 6 mph faster than my 24" Laser. Adding 5" of setback narrowed that gap to 2 mph.

Of course setback is a bad idea if the hull isn't solid.