What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

[liveboating]

What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV.
I do not have a jack plate installed yet.Running a 21pitch Laser11. Now running about 51mph.GPS at 5500 RPMS. It ran 47 mph with the previous 115 Yamaha on it. Is a jack plate goin to make a big difference?

 

[steelespike]

Re: What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

Pretty hard to predict. Your over 50 that's kind of a milestone. Prop calculator says your at a very respectable 6% slip.
Your at the maximum rated wot rpm. A jack plate can get the prop in "cleaner" water.
The go fast guys may have a suggestion or a guess. They say " the faster you go the harder it is to go faster".

 

[liveboating]

Re: What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

It just seems strange that only gaining 4 mph with a 150 versas 115.have talked to others that have simular boat setups that are running a strong 62 mph. but they are using a jack plate. Just wondering what kind ,of prop Maybe I should???

 

[steelespike]

Re: What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

The go fast guys may have some suggestions for more speed.Certain props give more lift than others If you have anything in the water like a transducer trim tabs or a foil on the motor. One or more may have to go.
There is no doubt a jack plate can make it easier to fine tune the height of the motor.A powered plate can be adjusted at speed.
I sure don't think a jack plate will add 10 mph unless the motor is very low now.
Is your motor presently raised as high as ventilation (prop grip)allows?
What size/weight is the Procraft?Is it intended to go fast? Is it a deep V or flatter bottom?
Is your motor in excellent tune? Don't assume because its a new install that the throttle opens all the way or timing is right.
If the Procraft is light and fast it seems you should be able to run more prop but as it stands 21 produces 5500 at a very respectable 6% slip.Speaking just prop size if you could turn a 23" up to 5800 rpm 6% slip you could get about 59 mph.

 

[liveboating]

Re: What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

My cavitation Plate is 1' above the very bottom of the pad. My boat hole weighs 1150 Lbs acording to Iboats and is 17.5 ft long does, not have a big V. Iam not using a foil. The motor Runs Like a top. never jurkes or stalls it does seem like it couldnt run any better.It has neever been worked on and has very low hours.I did check the throttle it does open all the way but I dont know about the timing.I tried a 25" turbo prop only got 5300 Rpms and 50MPH.I really appriciate your help so far.

 

[Philster]

Re: What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

You want to run a Tempest + @ 23p and move the AV plate up at least 2-3" above the bottom.

You are running into the engine's 5500 RPM limit.

You need a bigger prop. With a 23p Trophy, get the AV plate up 3" above bottom and hold on. Low 60's feels a lot faster than low 50's. It's 20% faster.

EDIT: changed prop to Tempest +. I always confuse Tempest and Trophy.

Also: biggest thing is not prop type at this point. 95% of the riddle is prop size and engine height.
.

 

[liveboating]

Re: What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

Thanks I will try it next week when I get back from vacation and will let u know the outcome.Thanks alot for the advise!!

 

[liveboating]

Re: What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

Is this what I need ?Tempest Plus Stainless 3-Blade Prop- 14-5/8 x 23 RH
I found one on ebay

 

[Philster]

Re: What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

The Tempest Plus is about the hardest 3-blade prop to beat when it comes to bass boats and shallow V boats.

That's the right size. But is hub/tube right for your engine? Please check. The Laser is a pretty snazzy prop, too. You just got the wrong pitch now for that Laser.

 

[liveboating]

Re: What speed should I get with a 1986 Procraft Competitor w/1990 Yamaha 150 ProV

I guess I dont know what u mean by( hub/tube )