Mercury 9.9 4 stroke

Joined
Apr 10, 2022
Messages
6
I have an older 9.9 merc. {1995-2005) I took the prop off and now it wont go back on. Is there a special procedure to line it back up?
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Welcome to Iboats,

No procedure, probably installed the rear prop spacer backwards ?

Happy Boating
 
Joined
Apr 10, 2022
Messages
6
I'm new to boating, like in, this is the first real boat I've ever owned This 9.9 is my kicker motor. What is a rear prop spacer? There is a spacer (washer) but it is forward and won't come off.
Let me explain what happened. I took the prop off because I bought a spare and wanted to see if it would fit. The prop came right off, when I tried to put the prop back on, it just wouldn't go back on. I thought it had to be lined up but no matter what, it won't slide all the way back on. It does slide a little way on but stops... Thats my story and I"m sticking to it!
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
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12,345
Are you trying to install other prop brand from the OEM currently factory delivered one? The spacer which I mean it's called a Thrust Holder and its located rear of the prop. When assembling back the prop must push all the way onto the prop shaft (1) trrust holder, (2) prop body, (3) washer, (4) nut, split pin (5) in that precise order. Must install the round thrust holder firstly when installing new OEM props and assume any other prop brand as well...

Happy Boating
 
Joined
Apr 10, 2022
Messages
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I guess I'm not explaining myself very well. I'll try again.
I took the prop off and the original one wont go back on. The spare prop I bought is identical to the original prop. (the spare prop is not an aftermarket prop. It is an original 9.9 mercury from another motor that is brand new)
Neither props will go back on.
 

briangcc

Commander
Joined
Jul 10, 2012
Messages
2,360
Here let's attack it this way...(and see if I got it right in the process)...

Prop 1...original prop that was installed on motor. Removed with no issues and set aside. Correct?

Prop 2...spare prop that won't seat onto your motor correct?

Then after seeing Prop 2 won't go onto the motor you tried reinstalling Prop 1 and that won't seat either, correct?

If I have all that right, and it'd be a miracle if I do, then I'd check the prop shaft to see that it was clean of any debris.

Probably not correct BUT...if it were my motor, I'd spray some brake cleaner on a rag and start cleaning the prop shaft till it was clean. Try Prop 1 then. If it goes on, light coat of grease on the shaft to keep the prop from seizing on the shaft and away you go. You can try Prop 2 at this point to see if it now slides on - provided it has the correct number of splines for your prop shaft.

**Might also check out the insides of both props to see if the splines have any debris in them.
 
Joined
Apr 10, 2022
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you understand.
Both props only go on part of the way. They go on all the way if you turn them backwards and slide them on. But when you turn them the right way, they only go on a little way.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
First time scenario reading such thing. Can you post for visual clarification a pic showing the prop fully installed backwards.. If the prop and shaft splines are not damaged, are clean and well greased it's a straightforward operation to skide back any prop specially the onre previously removed.

Happy Boating
 
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