How tight to make the prop gear carrier 9.9 Merc?

alcock lake

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Aug 2, 2007
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I just replaced the water pump (easy :) ) and the prop shaft seal on my 1987 Mercury 9.9; apparently there were two versions, one used a single seal, the other two seals back to back.

It goes without saying that the shop gave me the wrong set (in this case the wrong set was the two seals:mad:). The right set was one seal (and its smaller than the double seal set).

After I got that snafu dealt with I replaced the single seal and did the O ring that goes on the outside of the piece that unscrews (unscrews clockwise by the way).

My question is;

How tight do I screw this carrier back in, I guess I over did it a bit because it got bound up and wouldn't turn :eek:, I backed off about 1/4 turn and the prop shaft rotates now :).

Is there a "golden rule" or torque value I should be refering to or is this OK the way I did it?
 

Laddies

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Re: How tight to make the prop gear carrier 9.9 Merc?

80 ft.lbs. Something is wrong in the unit it should not bind.
 

alcock lake

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Re: How tight to make the prop gear carrier 9.9 Merc?

Wow, thats big torque and I was afraid of that, any ideas what it could be? It seems like a real simple install.

Also should the gear carrier go hard up against something in there (I assume thats what you torque it into)

and how do you measure torque when the deepest socket I can find is nowhere near deep enough to get over prop shaft. It would have to be about 4 - 5 inches deep.

I have a Snap-On 1/2" drive dial torque wrench so it can read even though its a left hand thread, problem is it seems only an open end wrench can get on the "special shaped nut" to torque it on.
 

alcock lake

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Re: How tight to make the prop gear carrier 9.9 Merc?

NEVER MIND!

Sometimes I amaze myself by just how stupid I can be,

I torqued the gear case into the bottom end and then tried to turn the prop shaft with the special 3 pronged nut still engaged in gear case, no wonder it wouldn't turn.

All I did was slide the nut back along the splines and sure enough the shaft turns like its supposed to. I wasn't able to measure the 80 lb/ft but I turned it for all I was worth with the open end wrench....gotta be close:eek:

Last question; and its related (I think)... with the o/b in forward gear I can tun the prop forward by hand, as though driving the boat forward, and I hear a click, click sound, I think the dogs in the clutch snapping over the ramp.

IS it supposed to do this, I don't think my Johnson does this (its at the lake and I can't confirm)?
 

Laddies

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Re: How tight to make the prop gear carrier 9.9 Merc?

I have a spanner that is like a piece on pipe with a 1/2' square drive in the one end that we use. got it from mercury. I checked a couple of other manuals for causes for it to bind and didn't have any luck but did find in the newer manual they have change the torque to 60 ft.lbs. so thats a help. Could you use a crowsfoot on the nut or you may have to weld a couple sockets together. Back to the binding I think if you remove the carrier and check it out and when reinstalling hold up on the drive shaft and turn it a little while tightening it will be OK.
 

AMD Rules

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Sep 23, 2004
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1,707
Re: How tight to make the prop gear carrier 9.9 Merc?

Sounds like you've got it all sorted out.


Holding the driveshaft from turning, then test the prop:

Neutral: prop freewheels either direction
Reverse: prop wont turn either direction
Forward: Prop wont turn CCW and will ratchet CW

You got it.
 
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