prop sugestions

[lekslk]

I have a 1987 stratos 181-pro 18'1" 92" beam probably around 2200-2400# fully loaded & I am running a newly rebuilt 2000 Johnson J150splssc 150 V6 gear ratio of 14:26 (.540) is what book says. motor 3 1/2" below the pad w/ a 6" jackplate. I currently have a 3 blade 20PX14 1/2" raker prop & motor is turning 5800-5900 motor trimed up at a speed of 55-57 mph on speedometer. Boat is completely restored (with some help from the guys in the building forum...Thanks so much for input) so it is not water logged or heavier than it would have been new. This is the prop I ran on my old 140 & I am not sure what to run on this one. It planes very quick. How far should you trim a set up like this up, or should you not trim it at all? Do I need a water pressure gauge. Any opinions would be greatly appreciated.

 

[lekslk]

Re: prop sugestions

Should I have put this question some where else?

 

[steelespike]

Re: prop sugestions

A 150 is a little beyond my experience. It is rated at 5,500.
I think your speed is very respectable. a 22 in pitch would put you closer to that 5,500 figure and may squeeze out a little more speed at the expense of some hole shot.Stick with the raker prop unless someone specifically suggests different.
If your not having any venting problems you could raise it a hole or 2.As far as trim;
trim to the best rpm and speed.If your going to play with extreme height and trim a pressure gauge probably makes sense.

 

[Dhadley]

Re: prop sugestions

The numbers are a little bit off but that's OK for now. The Raker is a good choice for that hull. I kinda doubt the AV palate is 3" below the pad. It might be 3" below the transom step or the propshaft might be 3" below the pad though. Let's clarify the numbers and go from there. Yes, a water pressure gauge would be a big help when changing the set up. Good point.

 

[lekslk]

Re: prop sugestions

Yes, I meant the prop shaft is about 3 1/2" below the pad. I don't know how to set it up for sure & want to get it right. I had it out yesterday on pretty smoothe water & ran right around 5800 rpm @ 56-57 on the speedometer. A local fella had a raker 22Px14 1/2 for 125.00 & I was thinking it may be a closer match to the new motor.

 

[lekslk]

Re: prop sugestions

I really appreciate the help around here, what exactly would the water pressure gauge tell me, when to stop trimming or raising? What should the pressure be?
Thanks so much