Merc 9.9 prop removal

I bought a '92 Merc 9.9 that has been hardly used. I have it in good shape for this season, but when I tried to remove the prop to grease the shaft, the nut won't budge. I have sprayed BP Blaster for the last 4 days. When I put the piece of wood between the anticave plate and the prop there is plenty of "give" when using a breaker bar. Should I put it in forward to take away the "give"? Will that damage the prop shaft? Can I use an impact?

any suggestion welcome

Tony

I've never had one not come off with the block of wood.I would not put it in gear.On my newer Merc the prop nut is plastic.

crazymanme2,
Mine is not plastic so maybe a little heat might work. From the looks of the nut, the prop has never been off.

I'm guessing you have removed the cotter pin. Could there be some other type of lock?
Could it be left hand threads?

No cotter pin that I can see, user manual does not mention one. It says to remove nut counter clock wise.

try automatic transmission oil i've seen that work great on pistons that are froze in a engine block

A little heat would not hurt.I would use oxy-acetylene torch not propane.

Thanks for the ideas. I will keep applying the BP Blaster for a few more days then heat the nut and try again.

retiredff said:

No cotter pin that I can see, user manual does not mention one. It says to remove nut counter clock wise.

Click to expand...

I'm thinking there has to be some type of retainer to keep the nut from coming loose.

lckstckn2smknbrls,

If you mean like a double nut, I'll check for that.

This is my first OB motor so some of the safety features will be new to me.

Tony

Tony, go to boats.net and pull up your engine according to serial number. Find the prop shaft blow up schematic, and it will show you what's there.

If it's a nylock nut, heat will destroy it.

I saw some with what they call a spacer, but it has a hex design to it, then the prop nut, also with the hex design. It does seem like a locking nut set up.

Bobg,

I have the service manual (PDF). It shows a "spacer" and "prop nut" BOTH are HEX shaped! That may be the problem. After my coffee kicks in I'll check and post my reply.

Tony

Yep, it has 2 different sized nuts. I removed the smaller outside nut, the main 13/16" nut will not budge! I soaked it w/BP Blaster and will try tomorrow...

Tony

Fixed it.. :?

As I stated earlier, I have never owned an outboard.

With that in mind, the first nut came off easily and was the smaller of the 2. The next nut, or so I thought, was a spacer shaped like a nut. I tried to remove it with a socket, but it is splined...

It along with the prop slid off.

Thanks for the help

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