85 force propeller replacement

sidewing

Seaman Apprentice
Joined
Aug 9, 2024
Messages
46
So my prop has been pretty badly dinged up.. time came for me to finally replace it. after scouring the forums here and the internet.. it was either take a chance on a 70 dollar aluminum 15 spline 13.25 17p or buy used already with some dings on it for $200+ off ebay.. i decided to take a chance even though i saw a lot of the old threads where Frank and others discussed it...

So here is what i ran into:
- Found the prop threading nut size is 1 inch, not 1 1/6 inch.. so the flo torque II hub kit nut wont work.. i had to reuse the old one..
- Found that the thrust washer inner was very slightly off.. the old one has a little taper, the new one doesn't.. (probably the difference between 4.25 and 4 inch that i was reading about).. had to reuse the old one. the new one had a very very slight wobble.. didnt want that on my prop.
- The taper on the back of the new prop was very slightly too large.. i read that Frank said its ok to cut it off.. i did this (not an easy task)... seems ok..
- Once to this point, i found that the metal rubbed 3 metal points inside the new prop.. i had to drill these down enough for clearance so it didnt rub... once i was clear, i tightened it down to 60ft LBS, only to find it was still very slightly rubbing.. removed it and drilled it down some more..

it finally seems like its fine. on there solid, no wobble, a little gap between the prop and the unit (i assume is fine?) where the taper was cut off.

in hind sight, probably easier to buy one that just slides right now lol.. this was 4 hours of work doing all the cutting and grinding.

looking for some opinions as to whether this is ok, a big NO, or anything i should look out for?

here's some pics:
 

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sidewing

Seaman Apprentice
Joined
Aug 9, 2024
Messages
46
Torqued it to 60ft lbs and it had a little bit of rub, so I grinded the 3 innards down a little more (it was only 1, but I didn't want to do it again so I took em all down a little more)...
Resembled and torqued.. spinning good, no rub.. seems good.. here's the final pics:

i guess the question i have for anyone, is there a way so i DONT have to grind down the 3 metal things inside next time.. like a spacer that i can add behind the thrust washer? cutting off the taper on the back of the prop isnt that bad... but the grinding down those 3 things with a drill bit was kind of a pain and worked my dewalt drill hard.
 

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jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,037
Next time just send the old prop out to be reworked. I think
just about all boat sales places can get that done.
Not sure anymore what the cost is but way cheaper and absolutely no rehabbing on your part.
 

briangcc

Commander
Joined
Jul 10, 2012
Messages
2,360
About 10 years ago, it was $50 to have my dinged up prop on the FourWinns repaired. Smacked rock bottom attempting to avoid a pre-teen in a 14ft aluminum boat w/outboard who's parents let him zip around the protected bay in.

Took a couple weeks so I had the work done off season.
 

The Force power

Commander
Joined
Feb 3, 2019
Messages
2,335
So here is what i ran into:
- Found the prop threading nut size is 1 inch, not 1 1/6 inch.. so the flo torque II hub kit nut wont work.. i had to reuse the old one..
- Found that the thrust washer inner was very slightly off.. the old one has a little taper, the new one doesn't.. (probably the difference between 4.25 and 4 inch that i was reading about).. had to reuse the old one. the new one had a very very slight wobble.. didnt want that on my prop.
- The taper on the back of the new prop was very slightly too large.. i read that Frank said its ok to cut it off.. i did this (not an easy task)... seems ok..

it finally seems like its fine. on there solid, no wobble, a little gap between the prop and the unit (i assume is fine?) where the taper was cut off.
looking for some opinions as to whether this is ok, a big NO, or anything i should look out for?
The 4" diameter is force prop. the 4.25 would be for Merc. and others??
The gap between the prop would be a problem IF this was a flow-through lower-unit due to the fumes leaking through the gap.
But this is not so for that reason; you'd be okay Now just hoping you're not picking-up fish-lines and/or small ropes
 

sidewing

Seaman Apprentice
Joined
Aug 9, 2024
Messages
46
I called a couple of places around here to see if they'd repair the old one. So far they say for outboards they usually just replace them. That they send it off for bigger direct drive props
 

The Force power

Commander
Joined
Feb 3, 2019
Messages
2,335
i guess the question i have for anyone, is there a way so i DONT have to grind down the 3 metal things inside next time.. like a spacer that i can add behind the thrust washer? cutting off the taper on the back of the prop isnt that bad... but the grinding down those 3 things with a drill bit was kind of a pain and worked my dewalt drill hard.
I would of removed the anode , that would of saved the hassle of doing what you did
 

sidewing

Seaman Apprentice
Joined
Aug 9, 2024
Messages
46
IF the motor is not for a looooong time in the water; NO OR shave down the Anode
Yup, just the two screws and wiggle off the shaft.
I thought about shaving it down but since I was in unknown land, i figured it was better to work the prop side just in case I messed up.. the boat doesn't stay in the water.. never longer than a day (morning to evening, usually not even that)..
Removal feels like the best option for me if I need to do this again.
 
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