Engine height???

[Mireco]

Hey guys- new to Allison- new to the forum, would love some input. During setup, I’ve always raised motor till about 15 psi @WOT (low water pickup lower/sportmaster) because of the relative indicator of a true running height (if that makes sense). But it seems a lot of people are using engine height over the water pressure indication. Who uses which and why? I have a 1997 2003 with hardly any lip (came like that) and a 225PM. Boat is running about 27psi water at 3/8” above pad, and from other posts I have read, seems only a brave few go higher than that for some reason? I know blowout:hooking becomes more of a risk but if careful testing/setup is done, should be pretty calculated I think. Just curious what the pros think... thanks for the input!

 

[Rick Propst]

im at 1 1/2 above the pad i have not lip at all,,

 

[Mireco]

im at 1 1/2 above the pad i have not lip at all,,

got it. Curious, what water pressure at WOT? Are you running a sportmaster? All holes open etc?

 

[Rick Propst]

my lower is stock getting ready to fill in the outer hole, my water pressure is 17-20 but my prop needs to be worked it needs to have the roll taken out and more cup added

 

[Mireco]

my lower is stock getting ready to fill in the outer hole, my water pressure is 17-20 but my prop needs to be worked it needs to have the roll taken out and more cup added

Will you fill both outer, Just 2 center open? How are you feeling/noticing the need to do that to the prop? Thank you for the replies btw...

 

[Rick Propst]

Was told to by a friend exdrag racer to fill outer hole in and deepen other the water inlet grooves will pickup 2 mph,, the problem with the prop is when I’m loaded to fish or with my wife riding beside me when I hit the gas the bow drops and it takes a lot of trim to get bow back up (this is with a 30et) I also run a 26 chopper cut to an et when I’m running the 26 I hit the gas the bow lifts great and prop runs great so I’m going to cut the 30 et to match it,, the 26 fully loaded with passenger runs 86 I run 83 with the 30

 

[Mireco]

Was told to by a friend exdrag racer to fill outer hole in and deepen other the water inlet grooves will pickup 2 mph,, the problem with the prop is when I’m loaded to fish or with my wife riding beside me when I hit the gas the bow drops and it takes a lot of trim to get bow back up (this is with a 30et) I also run a 26 chopper cut to an et when I’m running the 26 I hit the gas the bow lifts great and prop runs great so I’m going to cut the 30 et to match it,, the 26 fully loaded with passenger runs 86 I run 83 with the 30

What motor/rpm? Max unloaded mph?

 

[Rick Propst]

26 7200-7300 30 6800 6900,,,with the 30 I have run 91 unloaded but boat was still very wet so I know it has more

 

[stuart gary]

I run a 200 1/2inch above the pad with full lip. it has a hydromotive 26p 4 blade 6400rpm mid 80's with 15inch set back. boat responds really well with trim and speed.

 

[Mireco]

I run a 200 1/2inch above the pad with full lip. it has a hydromotive 26p 4 blade 6400rpm mid 80's with 15inch set back. boat responds really well with trim and speed.

I have a 26” Q4 hydromotive also, great prop all the way around! What water pressure are you seeing at WOT?

 

[stuart gary]

15 to 20.

 

[stuart gary]

engine runs at 150 degrees or less. never over 150

 

[David Shook]

Raise it an 1/8 inch at a time till it blows out then drop it 1/8 should be maxed out the only way to know if you have all of it !

 

[G Allen]

IMHO on the prop thang...see if you can get ahold of a 14.5/28 ProMax to take a ride on. It has no problem lifting the bow and it is one fast four blader...with a blade shape that looks like four slightly smaller ET blades. The resemblance is uncanny. And with the 8 nickel sized venting holes in the hub it spools up like an over hub prop on holeshot.

 

[whipper]

Raising the motor to high will actually scub top speed because you lesson the leverage and have more wetted surface. 1/4 below 1/8 below and up to even depending on load and prop. With a 14.5 to 15 inch prop you can get away with a little higher. You want the lip area { I know no lip} so pad area to be the only thing in the water and fairly neutral to slightly positive trim for fastest speeds. I do what Shook says to do. When your rpm goes up when you bump the trim and you loose speed back off one or two and thats the fastest you can go at that height trim ect... Experiment like that with different props because they will all be different. Best to use a digital GPS so you can see if you lost .2 or .5 of a mph to find that sweet sport and write it down with each prop. Then each time you use that prop youll know what you can do and what you cant to be safest. Have fun be safe and always were your PDF and lanyard. :] BTW its normal to get a different prop shaft height each time you measure just use your Gage and i mark mine were I like it.