Force 125 with a Comprop!

[MikDee]

First, to anyone having a hard time finding a prop, these are available, this is the pefect solution. On my 19' Bayliner ski boat model, It came with a 13x19" 3 blade Alum. Michigan prop. Being only able to reach 4500rpm, after all I did to this motor, (prob because it is tired, but does idle good now) I ordered a 17" pitch 4 blade (composite) Comprop because 1) it was available! 2) it was reasonable 3) it was light & strong 4) it was 4 blades 5) it had no rubber hub to slip 6) it had some good ratings, & reviews, from different boating magazines, found on it's main website, and finally 7) I find, It is all they claim , & more! (but not for heavy boats, or high horsepower) see it's limitations, but will work on most average outboard boats. Ok, after finally getting my motor not to stall going into gear, (apparently idle mixture adjustment was the critical item) anyway, out of the hole didn't appear much different, but the boat had more torque, and holding power on plane, & in turns, I immediately noticed the boat riding more bow high, at all speeds above idle! with my wife in the bowrider and a good chop, & wind, at the lake yesterday this was a good thing, less chance of getting wet. Next, when I wound it out, and trimmed it up, I got 4800rpm! (speedo said 40mph) the best I've gotten out of this motor so far, and finally I trimmed up as far as it would go with out any cavitation!,,, With my 19" prop, I could only trim up a little, before it would overrev, and I'd have to tweak it down some to get grip again.

I have only noticed this same full trim effect I got with the 4 blade Comprop, with a 3 blade "Rampage" stainless steel prop I recently picked up at a good price, but that's another story.

So, in conclusion I fully recommend the Comprop, (comprop.com) which can be ordered from Cabella's, and Overton's, website (Cabella's was cheaper I found out afterwards, to my dismay) anyway, hope this helps anyone looking for a new prop. Happy Boating, Mike

 

[Bigprairie1]

Re: Force 125 with a Comprop!

MD...refresh my memory, is it the higher the pitch the better the hole shot and the lower the top end? Do I have that correct? (ie: a 15" pitch prop vs. say 19" pitch would have better top end but not so quick out of the hole?).
I currently have the standard/original prop on my 90hp which I'm pretty sure is the 15". I'm not sure of the revs I get but the motor runs very well and I'm able to get into the high 30's mph wise. (...gotta get myself a tach shortly).

 

[MikDee]

Re: Force 125 with a Comprop!

MD...refresh my memory, is it the higher the pitch the better the hole shot and the lower the top end? Do I have that correct? (ie: a 15" pitch prop vs. say 19" pitch would have better top end but not so quick out of the hole?).
I currently have the standard/original prop on my 90hp which I'm pretty sure is the 15". I'm not sure of the revs I get but the motor runs very well and I'm able to get into the high 30's mph wise. (...gotta get myself a tach shortly).

Actually, it's quite the opposite, the lower the pitch the better the hole shot, and lower top end! Compare it to this, Lower pitch = 1st gear on your car, max torque, Min speed, as motor revs out. Higher pitch = like starting off in high gear, load on the motor, low revs till torque catches up, then highest top speed. Also, Diameter is usually a ratio set by the manufacturer, it usually gets bigger with lower pitch, and smaller with higher pitch, to help the motor out.
That's why lower pitch, and slightly bigger props are better for tubing, & skiing.

 

[MikDee]

Re: Force 125 with a Comprop!

Attention moderator, Or to whom this may concern, Being as I do not know who you may be, or how to contact you? I notice this thread was moved, I put this post in the Force forum, rather then the prop forum, for one main reason being, to help Force owners find available props. After frantically searching iboats, & various other websites, I found it very difficult to find a prop, any prop? for most force motors, until I came upon Comprop, and some other composition prop websites. You see, apparently this is a non-issue with other brand motors, it appears there are many varieties, styles, compositions, and types, available for them. Hence my reason to post it there to begin with. Respectfully, Mike D.

 

[craig96us]

Re: Force 125 with a Comprop!

I also have a 19' Bayliner with 125 Force motor. I have tried a coule of different 19 pitch aluminum props. Both good for about 35mph. One at 4000rpm, and the other at 4200rpm. The boat is slow to come up on plane.

After deciding to try a Composite prop, I found that the choices were the Comprop 13X17, and Piranha 13X17. I decided to go with the Piranha because the blades are replaceable. Changing pitch is inexpensive compared to buying another Comprop.

The Paranha arrived this week. Installation was no big deal. I have the older single exhaust lower end. I didn't have to add spacers, or cut/remove the sacrificial annode.

I will try it this weekend, and let you knwo how it works for me.

 

[MikDee]

Re: Force 125 with a Comprop!

Let me know how you make out Craig, the reason I went with the Comprop is I was pretty sure of the pitch I needed, and wanted to try a 4blade, instead of a 3 blade (I didn't see a 4 blade offered for a Force on piranha's website?).

 

[craig96us]

Re: Force 125 with a Comprop!

Well I am a little disappointed... 37mph @ 4200rpm. The Piranha prop really hooked up well, and ran really smooth. No vibration from the prop at all! The only negative thing I can say about it is the prop blades do not match up with the hub as well as they should. The blades stand proud of the hub about 0.050" or so which must cause a bit of drag.

I made a few hard turns at WOT and the only way I managed to make the prop cavitate at all was when the motor was trimmed all the way up! This tells me that the prop blades not mating with the hub very well doesn't cause any obvious cavitation problem.

My motor doesn't idle well, so I am thinking that the reason I didn't see more speed and higher rpm may be more due to the motor being a bit weak than being over-propped. The previous owner of my boat left it outside uncovered for a few years, so I am also pretty certain that all of the flotation foam below the decks is saturated - so the boat is certainly heavier than it needs to be.

MikDee-- You are right, Pirahna doesn't make a 4 blade for the Force motors. I am still considering a 15pitch 4 Blade Comprop for pulling skiers... I would rather have more pulling power and be able to really snap out of the hole for skiing.

Overall, I have to give a "thumbs up" for the Pirahna prop. It works quite well.

I am planning on gutting and rebuilding my hull this winter. With the extra weight removed from my hull, the boat should run faster.

I did a compression test on my motor, and all four cylinders are about 160. I cleaned the carbs a couple of months ago. I checked my fuel filters, and they are clean. I was unable to get my timing light to flicker, so I don't know for sure if the timing is right or not. I believe my idle problem is due to damaged reeds, but have not pulled them out to check yet. Come springtime, I will pull it apart, and put Boyesen reeds in it.

Eventually I will get it all sorted out...