Prop Pitch on a 18.5 FS

[cfstar18]

Hi All,

New here, but I enjoy reading all the info. I have a 120HP force on an 1998 18.5ft Nitro 185 fish and ski. It has a SS Lazer 20 Pitch prop on it (likely original), but I don't think i am getting anywhere near top speed. My WOT is around 4850, which I think is the low end. I think the motor is running OK. Any ideas? Only getting about 34 MPH with two guys and all the fishing gear. Thanks all

 

[Irv964]

Re: Prop Pitch on a 18.5 FS

Hi All,

New here, but I enjoy reading all the info. I have a 120HP force on an 1998 18.5ft Nitro 185 fish and ski. It has a SS Lazer 20 Pitch prop on it (likely original), but I don't think i am getting anywhere near top speed. My WOT is around 4850, which I think is the low end. I think the motor is running OK. Any ideas? Only getting about 34 MPH with two guys and all the fishing gear. Thanks all

First you will need to know exactly what max rpm your motor is rated for then you will need to know what max rpm you are reaching at WOT(wide open throttle) with your current prop/setup.
You want a prop that will take you into the upper end of your motors max rpm range. This link is a good read as well as other posts on here that talk about engine height. ...........Irv964
http://turningpointpropellers.com/propellers_101_cm.htm

 

[cfstar18]

Re: Prop Pitch on a 18.5 FS

hi..thanks for the reply. It is rated for 5350 and I am getting 4850 WOT and 34 MPH

 

[steelespike]

Re: Prop Pitch on a 18.5 FS

Before a prop investment you should confirm the motor is sound a compression check and tuneup is a start.Be sure the throttle opens all the way.Fine tune your setup starting with the antivent plate even with the bottom raise the motor a hole at a time to a point just brefore venting becomes a problem.Be sure it pumps water.With a sound motor and good setup get back with the max rpm and speed.When selecting props try to stick with the same brand and model only changing pitch unless specifically suggested by an expert.

 

[cfstar18]

Re: Prop Pitch on a 18.5 FS

Hi..thanks,

Compression is great and everything has tuned and plate already installed. The only thing I have not done is change the mount angle of the motor. Do that before changing props?