20ft CC boat with 150 johnson top speed

[jwellcraft]

What should I expect the top speed to be on this 1989 Centre Console sport fisherman Wellcraft boat with a 1994 Johnson 150 motor on a 3 blade 14.3 X 21 aluminum prop.

 

[jonesg]

Re: 20ft CC boat with 150 johnson top speed

I guess around 50 mph if you can get the rpm's at 5500.
It also depends on the chop and weight of the boat.

 

[tashasdaddy]

Re: 20ft CC boat with 150 johnson top speed

i would want that motor to turn atleast 5800. too many variables to give you speed.

 

[ezeke]

Re: 20ft CC boat with 150 johnson top speed

At 5500 RPM the theoretical (no slip) maximum speed with a 21 pitch prop on your motor would be 59 mph.

Gear ratio for the model is 1.86, do the math here: http://go-fast.com/Prop_Slip_Calculator.htm

 

[w2much]

Re: 20ft CC boat with 150 johnson top speed

My 21' Striper with 150 Evinrude turns about 5500 RPM WOT. Depends on how many people, bait tanks full or empty, case of beer and ice? I would say don't expect over 40MPH + or -.

 

[Shamus O'toole]

Re: 20ft CC boat with 150 johnson top speed

40-45 mph...

 

[jwellcraft]

Re: 20ft CC boat with 150 johnson top speed

Thanks for all of the replies but I think my voltage regulator is bad in the motor because when my tach reaches 4,000 rpms it drops back down very low and to zero sometimes (no change in motor output though) so not sure on the max rpms. The fastest I ever recorded on my Garmin GPS is 38.4 MPH and that was with 3/4 tank of fuel and the other day with 1/4 tank I only got 36 mph. Do you think the 21 pitch is ok and not too much prop for that motor and boat?

 

[ezeke]

Re: 20ft CC boat with 150 johnson top speed

If your GPS speed is accurate at WOT, I think that you are over-propped and lugging your engine, shortening it's life.

 

[jwellcraft]

Re: 20ft CC boat with 150 johnson top speed

I think the prop is to big yes because when the motor does open up it doesn't really scream likes it's wide open and as far as I know the GPS should be accurate. When I purchased this boat it came with this prop and didn't have a tach so I purcahsed one. How do you think a 17 pitch would run it?

Thanks

 

[ezeke]

Re: 20ft CC boat with 150 johnson top speed

17 pitch will give you a much better hole shot; better for your engine and you should still get near 45 MPH at WOT with 10% slip.

I would try to confirm that you have a a reliable tachometer before running too much with a new propeller.

 

[jwellcraft]

Re: 20ft CC boat with 150 johnson top speed

Ok thanks, I will rectify the tach issue hopefully but it's the second new one which is a teleflex Lido series so I hope their a good brand. Any special brand prop I should look for? I think I will be sticking to the aluminum materials ones just for safety.

 

[BLU LUNCH]

Re: 20ft CC boat with 150 johnson top speed

I have 74 Wellcraft V-20 CC with 150 Merc Wot with a 17p I can get 42 MPH with a half a tank.
www.wellcraftv20.com

 

[ezeke]

Re: 20ft CC boat with 150 johnson top speed

Ok thanks, I will rectify the tach issue hopefully but it's the second new one which is a teleflex Lido series so I hope their a good brand. Any special brand prop I should look for? I think I will be sticking to the aluminum materials ones just for safety.[/quote]

For aluminum 3 blade props I like OE, but the Michigan Wheel props have served me well and I have not had any problems with the Solas props.

The iboats people are really quick on the MW & Solas props and their pricing is very competitive.

http://boatpropellers.iboats.com/Jo...andard&**********=758122405&*******=164296561

 

[jwellcraft]

Re: 20ft CC boat with 150 johnson top speed

Great thanks, are the Hustler props any good?

 

[ezeke]

Re: 20ft CC boat with 150 johnson top speed

Great thanks, are the Hustler props any good?

Honestly, the worst I ever owned - but that's just me (maybe).

I don't buy anything that doesn't come with the hub fixed in place anymore. MW Match and Solas Amita have that.

 

[jwellcraft]

Re: 20ft CC boat with 150 johnson top speed

Ok I looked at the Michigan wheel vortex and the one I selected has a seperate hub as well and isn't fixed. I will look at the match.

 

[junior1113]

Re: 20ft CC boat with 150 johnson top speed

pic in my aviater is my 93' hydrasport 2000 cc (20'2") with 93 200 hp evinrude im runing a turbo ult ima4x14.25x17p toping out around 48mph @6000rpm (empty) 21p is to much i would say 3x19 is pushing it. u should be able to hit low 40's empty. if motor is strong. i like turbos 4 blade props the most and i've tried 10 on this. my back up is an omc raker 3 x 18 and gets right at 50 @5800 but hole shot and rough seas with a load its junk

 

[jwellcraft]

Re: 20ft CC boat with 150 johnson top speed

Cool, I ended up purchasing a OMC 14.8 X 17 aluminum from the dealer so hope this is better and I hope I made the right choice.

Thanks

 

[jwellcraft]

Re: 20ft CC boat with 150 johnson top speed

Took the boat out on the new prop but really couldn't test due to weather but seems like it ran a little harder/quicker so I just fished for the whole day. The tach still did the same thing as it reached 4,000 rpm's it dropped back down and bounced back up a little but not over 4,000 so I think I need to change the rectifier/regulator.

 

[ezeke]

Re: 20ft CC boat with 150 johnson top speed

Took the boat out on the new prop but really couldn't test due to weather but seems like it ran a little harder/quicker so I just fished for the whole day. The tach still did the same thing as it reached 4,000 rpm's it dropped back down and bounced back up a little but not over 4,000 so I think I need to change the rectifier/regulator.

First, check to be sure that the dial on the back of the tach is turned to 6P.