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prop question for an o/b guru

justincase

justincase

Well-known member
My 150 v6 is running a 21p stainless at 5500 rpm wot, how much holeshot will i lose going to a 23p laser2 and how much mph is gained? i have excellent holeshot now
 
justincase said:
My 150 v6 is running a 21p stainless at 5500 rpm wot, how much holeshot will i lose going to a 23p laser2 and how much mph is gained? i have excellent holeshot now
Click to expand...

I had a 23p ss on my 150hp inline six when I got it top end was great but the hole shot sucked . I had a 19p ss I put on and it got out of the hole better but wasnt fast enough . I put on a alum 21p and have been pretty happy with that .
 
I'm not gonna pretend I'm a guru, but I think you might actually gain speed (and holeshot) by going down to a 20p. Seems like that 150 should have some engine speed left in it!
 
We need all the numbers first to determin the outcome. What year is that 150? Is that 5500 the highest the engine will turn with the 21? What speed (gps) are you getting with that max rpm?
 
illMATTic said:
We need all the numbers first to determin the outcome. What year is that 150? Is that 5500 the highest the engine will turn with the 21? What speed (gps) are you getting with that max rpm?
Click to expand...
Matt no gps and 5500 is the highest wot, black max 1986
 
ToP_Enticer said:
I'm not gonna pretend I'm a guru, but I think you might actually gain speed (and holeshot) by going down to a 20p. Seems like that 150 should have some engine speed left in it!
Click to expand...
Why would i go down in speed and go over 5600 revs and blow the motor??????:shakehead:
 
Well you wont blow the engine. A 60degree V6 Merc is good for over 6K rpm all day long. I wonder why you are only turning 5500rpm? I can turn 6300 rpm with my 150 Merc and a 21P on my Spectra which is a lot heavier then your exciter.

ToP Enticer was only trying to help you.
 
you will get alot of opinions on this one.....
the max rpm all depends on who you talk to. on my 2.4/200 i have been told if i run it over 5200 or so it will not last long at all, like for the rest of the summer. with that said i have ran it at 6000 and above (up to 6400) for three years now. everything is fine. i know others on here turn 2.4's to 6600 and 6700 also!
with your 150-i would think you could turn it up close to 6k w/ a 21p.....
how much trim you have at 5500? mine turns about 5600 wot at rest and when i start trimming i watch it gain between 400 and 500 rpm depending on water conditions;)
i am running a 23p tempest plus 14 1/2. i was turning a 23p laser2 13 3/4.
from the laser 2 i went w/ a 25 laser 2 and dropped about 300rpm. hole shot wasn't great and lost top end due to the lower rpm......

all that b*llsh*t said your rpm is more important than the size of the prop-you need the mota to run at it's most efficent state to get a good speed,holeshot, and reliabilty:thumb: my 2 cent.......fire away boyz:p
 
Ok my bad! i didnt have my glasses on the other day, just went and looked at my tach and red line is 6000 its running about 5950. i dont know why i was thinking 5500
 
As far as i can tell and it runs 5900 to 6000 every time, the reason im asking winter project is a jackplate and someone wants my 21p even for their new 23 p laser2
 
when you sit in your seat there is a lever to your right, it controls forward & reverse operations along with throttle control. if you push the lever ALL THE WAY forward it will make your boat faster!! :poke:

:rof:

:banana:

the lever may look like this..

images
 
OK, you MUST geta GPS reading this season. ;)

My best guess at your speed right now is 54 mph. How did I arrive at this speed? I will tell you.

5900 rpm, 2-1 gears, 21P, 8% slip, nets you 54MPH.

You may even be turning higher rpms at times since the tach could be maxed out and not even know it.

Jackplate + 23P prop = MORE SPEED :banana:
 
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