Force 125 stainless prop

[SkiDad]

I picked up a 15 pitch Michigan stainless prop the other day for pretty cheap. Been looking for a long time - hard to find that pitch. Didn't give them too much b/c i couldn't test it for spun hub, etc. I haven't tested it yet b/c the thrust washer doesn't hit flush with the back of the hub. It hits on the brass spline piece and there is a 1/8 - 3/16" gap between the hub and washer. Wasn't sure if that would hurt anything. Do I need a different thrust washer ?

And will i need a few washers in the front of the nut or some other kind of spacer ? The black flare piece I use on my other prop doesn't fit that deep.

1st pic i my aluminium prop that I bought last year... thrust washer works fine. The others are the stainless prop and thrust washer.

PS - any issues running a stainless on force - this prop is DANG HEAVY.

 

[Frank Acampora]

Re: Force 125 stainless prop



I can see from the last photo that the hub is NOT pressed into the prop all the way. The bronze insert should be flush with the face of the center prop hub. If you have a good press you may be able to press it in further.

However, moving the hub now MAY break the bond between the rubber and stainless. SO: Before you do that try this. There is enough flex in the rubber hub so that if you tighten the prop onto the shaft, the bronze insert will be forced forward.

Depending upon the year of the Force, you may need a 1/4 inch spacer between the prop hub and the prop nut washer. Early Force engines were designed with the prop shaft long enough so that a special "flare washer" could be used along with a tail cone.

The last two photos are from a Ballistic prop which needed special modification to fit. Middle photo is a Mercury bronze racing prop. You can see the 1/4 inch spacer under the prop nut and washer.

 

[SkiDad]

Re: Force 125 stainless prop

my engine is an 1985 with the closed hub. The guy i got this from said his engine was an 1988 125, it blew something in the engine and he re-powered with a different brand. I know there were 2 types of 1988's some thru hub and some not - not sure what kind his was. He wanted 100 bucks, I ended up giving him 70 bucks for it. It's in decent overall. There was a little splits in the rubber part that is why I wasn't too keen on the 100 bucks. Well if it doesn't work it it will be a nice spare to get me off the water if needed or I'll get it rehubbed and polished. I'll get some washers and try tightening it down.

Will stainless be harder on my engine when shifting. I've been boating for 43 years but we have always had aluminum props.

 

[Frank Acampora]

Re: Force 125 stainless prop

If your engine is a 1985 you will definitely need a spacer--nothing special, a couple of big brass or stainless washers, as long as combined they are about 1/4 inch. The prop will fit and there will be NO DIFFERENCE in performance between it and the same pitch closed hub prop.

I personally don't believe the horror stories and old wives' tales about stainless being harder on the lower unit. Stainless DOES give a performance increase over the same prop in aluminum. Quite frankly, I sell all my aluminum props and only keep one as a spare. Given the choice I will use nothing but stainless.

70 bucks is a decent price for that prop. If it needs to be re-hubbed, the hub costs about 20-30 and the prop shop will probably charge you about 60. So: 135 for a stainless prop is a fair price. If you have a press or have access to one, you can re hub it yourself. See my reply to the other post about changing an OMC hub to a Merc.

 

[SkiDad]

Re: Force 125 stainless prop

I got 3 washers today. When I tightened it up it took up the slack. When i take it off it springs back. Going to give it a spin tomorrow. Thanks Sir.

 

[SkiDad]

Re: Force 125 stainless prop

took the new SS prop out last night - the hole shot was noticeably better and it was already pretty quick. But I did notice some odd things. The stern rode higher than before. The steering was harder to turn too and was torquing some. If I trim up the steering was odd. I tried leaving the engine about level with the boat and it seemed to run best like that.

with the SS my RPM dropped about 300 and it was about 2 MPH slower than my aluminium prop - i swapped them while in the water. Aluminum was 5100 (39 mph) and stainless was 4800 RPM (37 MPH). I'm guessing it's the cupping and also b/c the prop is 5/8" wider. My AL prop is 13 1/8 x 15 and the SS is 13 3/4 x 15.