How to Remove Brass?

LaqueRatt

Chief Petty Officer
Joined
Jun 27, 2022
Messages
444
Bought a new prop for my 77 25 HP rude: Michigan Match 3-Blade Aluminum Propeller (012013) Supposed to be a direct replacement for the original OMC 388088.

All seemed good until I tried to install it. The old prop has a larger motor side bore which looks to extend down about an inch. I can see a step in it. Everything else is fine. The difference is pretty small, but enough to prevent the prop from going on: Old: 17mm New: 15.75mm.

Is there an easy way to create this small recess needed to fit the prop to the shaft? I was thinking of just drilling it out with a bigger bit, but don't think have one the right size. Can you just buy single bits in various sizes? I don't have a lathe or a mill, but I do have a dremel with some stones and coarse grinding drums and a drill press available.

Don't have many options here, so would really like to make the Michigan prop work.
 

LaqueRatt

Chief Petty Officer
Joined
Jun 27, 2022
Messages
444
Never mind. I got it on with a little pursuasion. It fits tight, but it fits! Should I grease the shaft? I'd hate to not be able to get it back off if I need to.
 

JohnSz

Cadet
Joined
Aug 9, 2023
Messages
28
Never mind. I got it on with a little pursuasion. It fits tight, but it fits! Should I grease the shaft? I'd hate to not be able to get it back off if I need to.
Glad you got it on. Yes, grease the shaft. Most motors it is part of the yearly maintenance.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,446
Never mind. I got it on with a little pursuasion. It fits tight, but it fits! Should I grease the shaft? I'd hate to not be able to get it back off if I need to.
A 1.25mm difference would require an Impossible amount of Persuasion.
 

LaqueRatt

Chief Petty Officer
Joined
Jun 27, 2022
Messages
444
You'd think so wouldn't you? Not so. The original prop had that much slop in the bore. The new prop fits very snug. Greased the shaft and tapped it home with a rubber mallet. Haven't had it out on the lake yet, but think it's going to be OK.
 

flashback

Captain
Joined
Jun 28, 2002
Messages
3,963
The old prop was never greased and now you know how to remove brass!
 

harringtondav

Commander
Joined
May 26, 2018
Messages
2,439
I have a unopened cartridge of Merc 2-4-C with teflon (PTFE) plus a gun half full of the stuff.
Best prop shaft grease in my mind. Waterproof and always on the splines when I pull my props. Also great for prop thrust plates, gimbal pivot pins or any other under water joints. I've gone VP now, but I'll always have this stuff on hand.
 
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