18' v-hull over propped or?

[shirthero]

Hey guys, I have an 1978 18' deep v glastron with a 78 115 evinrude on it, we get better each weekend but still not a real good hole shot. Had a spun 13.75X19 prop, just put a new hustler 14.25X19 on it, lowered the motor by 1.5" so the cavplate is now even or just a hair below the hull. Full decarb today, compression after 120 all four jugs (YES!) I dont have a tach but with the family of 4 we take 20-30 seconds to get planed, me alone up and get 5-10 seconds. Any thoguhts??? Step down to a 17 pitch?

 

[ezeke]

Re: 18' v-hull over propped or?

You need a prop that will allow the engine to reach 5800 RPM at WOT with a normal load. That will prevent lugging the motor.

You can't get a good setup without a tach unless you do it with a stopwatch and GPS, and that will not be as accurate.

 

[Dhadley]

Re: 18' v-hull over propped or?

Hummm...a 14 1/4 diameter prop (and most 13 3/4") are for V6s not V4s. Lets verify what brand & style prop you have. Then make sure the AV plate isn't below the hull. You don't want it any lower than even. And that's probably too low anyway.

 

[shirthero]

Re: 18' v-hull over propped or?

I lowered the motor mainly cause
i was having so much trouble with the prop cavitating if I turned very sharp at all, I've had, driven numorous boats over the years and this boat would rev up way too easy if the motor was turned vey far-but the old prop was spun when we got it apparently. I bought the prop off here, i researched the buy at a lot of websites, they all had it at 13.17-14.25, the hustler just comes in this diameter,
i have been wondering if the increase in dia needs a corresponding drop in pitch. The boat had 3 props, all were 13.75?X19, no doubt factory/dealer setup gien the boats history.

 

[shirthero]

Re: 18' v-hull over propped or?

CORRECTION
new prop is 13 1/4 X 19
old prop 13 X 19

 

[72SideWinderSS]

Re: 18' v-hull over propped or?

It sure would be nice to know what is your WOT gps speed and RPM's with the new prop setup the way it is now.

 

[steelespike]

Re: 18' v-hull over propped or?

The Turning point will allow more height than a regular al. prop.
You want to have as little motor in the water as possible.At 1 1/2 inches you could gain close to 2 mph and a little hole shot.
The 19 may be too much prop but you can't tell anything without your max rpm and speed.

 

[shirthero]

Re: 18' v-hull over propped or?

ok the project for the next few days, install a tach and move the motor back up, now you have me wondering if I should come up a little higher than original, were you saying I can get away with 1 1/2" above the bottom with the cav plate?

 

[72SideWinderSS]

Re: 18' v-hull over propped or?

ok the project for the next few days, install a tach and move the motor back up, now you have me wondering if I should come up a little higher than original, were you saying I can get away with 1 1/2" above the bottom with the cav plate?

I would come backup to where you originally were. Then see if you need to go up or down.