Stuck Prop?

road kill

Seaman
Joined
Aug 22, 2010
Messages
52
I just picked up a nice running 1977 Mercury 402, its in great shape other than two issues. First, the prop is stuck on the shaft, it's in good shape and works fine on my boat, but I usually like to keep the splines lubed to prevent it from seizing.
Second, the wiring from the big plug on the side of the lower pan to the motor is shot, the rubber is gone and it's a mess of rotted wires and tape right now.
(I hardwired it direct for now but would like to put it back to original).

What is it with Mercury motors that makes the props seize on? I've owned many other motors, and every Mercury I've owned has come to me with a stuck prop, in most cases I cut the prop off bit by bit, but this prop is in good condition. For right now I soaked it with penetrating oil lubed up the washer and nut. I'll run it a while and retry it I guess. I'd just like to know that if I had to change a prop, I could do so on the water.
Any tricks out there to get one of these props off without total destruction?

Does anyone make a new wiring harness for these?
(Or am I just better off running it wired direct with no plug at the motor?)
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Re: Stuck Prop?

Fill out the profile section,you might be close to someone who can help.
Salt or fresh water? PB Blaster for a couple of days.
Then a 3 jaw puller.Remove the arms,replace with 3 sections of chain about 18" long. Loop the chain around one blade and bolt it through the puller.Do this with the other 2 and you have a handy dandy homemade prop puller.
I have used this to pull props off of motors that have never had any grease.
If it's really stuck it will pull the prop off the hub and you'll end up cutting the rest off the shaft.Use LOT"S of grease when you replace the prop.
The prop should have a grounding washer in the system to stop corrosion, most get thrown away.J
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: Stuck Prop?

Tilt the motor up and apply the penetrating oil. Let it sit for a while. Now take a 2X4 and use it to pry the prop blade against the gearcase vertical part. Sometimes you can coax them off. Use good marine grease on the splines, after you clean them up.
 

road kill

Seaman
Joined
Aug 22, 2010
Messages
52
Re: Stuck Prop?

Its been soaking for a week, and no luck, I made a prop puller from 1/4" J bolts and a flywheel puller but that won't budge this one. I even took a spare prop with me today, ran all day with no nut or washer on the prop figuring that would maybe work it loose, but its not moving. The motor don't appear to have been in saltwater, I bought it in north/central PA but I'm sure it could have had the occasional trip to either NJ or MD into some saltwater. (There's no corrosion anywhere on the motor, just some faded decals, the rest of the thing looks like new).
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: Stuck Prop?

OK, Time for the Dremel tool and a cold chistle to crack off the brass Prop hub?
 

road kill

Seaman
Joined
Aug 22, 2010
Messages
52
Re: Stuck Prop?

OK, Time for the Dremel tool and a cold chistle to crack off the brass Prop hub?

I'd have already done that if the prop didn't look like brand new.
Why is it only on Mercury motors that I keep running into stuck props?
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Re: Stuck Prop?

It isin't only Mercs.It the lazy owners.Do the puller and chains.It's never failed.J
 

BayouRunner

Petty Officer 3rd Class
Joined
May 9, 2010
Messages
79
Re: Stuck Prop?

Road...I had the same prob with my '90 115. We used a large flywheel puller, but bolted sections of chain around the blades and used an impact gun..like the ones used to get lugs on/off wheels...to FINALLY coax the prop off the bushing. The bushing was stuck on the shaft so good, we used a torch and chisel...AFTER shaving as much rubber off the inner hub of the bushing as possible. After torching, we used a cold chisel to split the aluminum housing of the bushing. NO DAMAGE to the prop or the shaft whatsoever. I'm guessing the aluminum of the bushing and the stainless of the shaft, without good lubing, is creating a "weld" cause of the dissimilar metals?? Mine was corroded to the point that it was aluminum and aluminum powder after extraction. All I know is I lubed the democrat out of the shaft before putting the new prop on.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Re: Stuck Prop?

If it's not too stuck it will be reusable.You need to get a tube brush to clean it out.
And LUBE it LOTS!!!! J
 

road kill

Seaman
Joined
Aug 22, 2010
Messages
52
Re: Stuck Prop?

I made up a chain puller using a fairly heavy duty OTC balancer puller and even heated up some penetrating oil and soaked the hub and shaft, nothing doing. The prop will shear off long before the hub lets go. The prop hub appears to be brass on this one.
I also made J bolts which grab the prop through the exhaust port area, they catch the prop right near where the webbing starts off the hub center. I figured this was most likely the strongest point. Still nothing moves. I would have figured that the prop would have slid off the hub if nothing else but it just flexes a bit and goes right back in place. There's something stopping it from just sliding off, it goes about 3/8" and stops dead. I'd settle for losing the hub, I can rehub the prop no problem. At least that's better than $100+ for a new prop.
 

ecs17a

Cadet
Joined
Nov 7, 2010
Messages
18
Re: Stuck Prop?

Try Inox penetrating oil if you can find it.Worked great for me.
 
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