40 hp Mercury 2stk, exhaust tube question

halmc

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This question will relate to the following engine:

MERCURY - ( 40 H.P. (1994 ))
Serial No: 0G082643 Model No: 1040412PD

Parts List for model 1040412PD:


And to the following illustration:


Referring to the exhaust tube that is noted with the red arrow, what fixes this piece vertically? The one in my shop is free to move vertically about 2", resulting in leaks of exhaust and water into the drive shaft housing.

Since I have a few guesses of my own, not sure I need another one. Yo, but if you know may I please hear from you.
 

Laddies

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Re: 40 hp Mercury 2stk, exhaust tube question

It sits in a rubber grommet on the bottom and the top is held in place with the tube that is cast on the bottom of the shift shaft plate
 

halmc

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Re: 40 hp Mercury 2stk, exhaust tube question

Thanks much. I'm pretty sure I'm gonna have to remove the power head to see exactly what's up, but would appreciate a point of clarification: We're both familiar with the tube that's cast on the bottom of the shift shaft plate, so I won't publish an image, but it is quite round, while the exhaust tube is not at all. That wouldn't make for a very good seal -- or perhaps the exhaust tube (with the red arrow) is pressed up against the shift shaft plate to make the seal . . . ? I don't see any soft sealing material at the top so assume there is none . . . safe assumption?

Lastly, considering the exhaust path from the shift shaft plate down, should one expect a good seal anyway?

And thanks for your on point answer.
 

Laddies

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Re: 40 hp Mercury 2stk, exhaust tube question

Most tubes the only seal at the top is carbon and it is quite common for it to move when the unit is dropped, I've seen 6s that would move 4" or more. If you remove the powerhead to look at it, you could clean both tubes and with the tube seated into the lower unit seal the top of the tubes together with high temp RTV sealer. While you have it apart don't forget to check the upper motor mounts.
 

halmc

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Re: 40 hp Mercury 2stk, exhaust tube question

Much thanks. This engine spits both exhaust and water from under the shift shaft late. I'm thinking that the spitting, while it may be annoying, is harmless, and if it is normally sealed with carbon, temporary. yes? (Perahps I should also add that the engine runs perfectly as long as one wishes to run it.)
 

Laddies

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Re: 40 hp Mercury 2stk, exhaust tube question

That's the motor mounts and the seals for them leaking
 

halmc

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Re: 40 hp Mercury 2stk, exhaust tube question

I'll bet you're exactly right, cuz that's exactly where the spitting is coming from! BTW, I'm working on this engine gratis for a nice ole retired Navy hospital corpsman whose main passion these days is fishing. He and I served in the Gulf of Tonkin some serveral decades ago, so your help is especially valuable -- to both of us.

Many thanks!

For clarification, we are talking about items 8 and 9 in the following illustration? And do I gather correctly that I can expect both the mounts and seals to need replacing?

 

halmc

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Re: 40 hp Mercury 2stk, exhaust tube question

Thnx, parts orderd.
 

halmc

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Re: 40 hp Mercury 2stk, exhaust tube question

Ugh! I have the parts in hand, but have concluded that the powerhead must be removed from the engine to access the top two motor mounts and seals.

Whereas it looks like #14 in the diagram above is on the outside of the drive shaft housing, it's actually on the inside. Thus to gain access to it -- the motormount and seal -- one would have to take the power head off, then reach in from the top of the drive shaft housing.

Right or wrong, please.
 

Laddies

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Re: 40 hp Mercury 2stk, exhaust tube question

Yes the powerhead must br taken off
 
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