Inline 6 Exhaust Tube Installation

H

Hydro Mark

Seaman
Joined
Mar 30, 2013
Messages
56
I have a 1968 Merc 1250 125 hp outboard. It does not have an Exhaust Tube and I found out, through some very helpful folks on this board (thank you members!) that I am supposed to have one. So I ordered one from ebay.
$T2eC16FHJGwE9n)ySdSDBQhuYnd0K!~~60_12.JPG
I have a Clymer manual and there's no info on the Exhaust Tube. On the picture (I don't physically have it yet) there are several holes and a bolt. Is it bolted in? Do I have to disassemble more than dropping the Lower Unit to install the replacement Exhaust Tube?

Thanks to anyone that can help.

Mark
 
H

Hydro Mark

Seaman
Joined
Mar 30, 2013
Messages
56
Re: Inline 6 Exhaust Tube Installation

Ok, I ordered the lifting eye, exhaust tube and seals.

Now my question is.....Is removing the power head a DIY project?

Thanks,

Mark
 
L

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: Inline 6 Exhaust Tube Installation

It's not difficult just time consuming when your ready I can PM you the removal process
 
H

Hydro Mark

Seaman
Joined
Mar 30, 2013
Messages
56
Re: Inline 6 Exhaust Tube Installation

Laddies said:
It's not difficult just time consuming when your ready I can PM you the removal process
Click to expand...

Also, I guess I should ask......is there any required hardware that I might not have, other than the two bolts shown in the picture of the Exhaust Tube?

Thanks,
Mark
 
H

Hydro Mark

Seaman
Joined
Mar 30, 2013
Messages
56
Re: Inline 6 Exhaust Tube Installation

Well, I got everything apart and it seems to me that I have some variant the does NOT come with an exhaust tube. There are two different exhaust extension plates. My plate is a 48712 and has no way to attach the exhaust tube. The other plate (52932) does. It also appears there are two different drive shaft housings, a 3376 and a 3669. Mine is a 3376.
Can anybody shed some light on this? I'm really confused now.


[img=http://imageshack.us/a/img824/7669/ydvf.jpg]
[img=http://imageshack.us/a/img51/5556/z7vc.jpg]
Thanks,

Mark
 
merc850

merc850

Commander
Joined
Jul 7, 2010
Messages
2,046
Re: Inline 6 Exhaust Tube Installation

Here's a cut open view of the whole engine and the housing page from the manual, the exhaust tube should bolt to the plate and go into a gasket in the LU
merc 900 2.jpgDriveshaft-house-1.jpg
 
E

emckelvy

Commander
Joined
Jan 16, 2004
Messages
2,506
Re: Inline 6 Exhaust Tube Installation

I've never seen one but they obviously exist! I found an eBay Australian auction where they sold the same plate:

Mercury 1250 Outboard Engine Tray TO LEG Exhaust Plate PN 48712 | eBay

Perhaps this was an early production model. The 1250 was a transition model, with 99 c.i. but still had the old flat-top-design pistons.

Maybe Merc thought this "open plenum" type of exhaust plate would work well, but I expect they found out the exhaust tuner/tube worked better. The latest part number for the plate is 48712A 2 so maybe they issued an updated version.

At any rate, I'm trying to figure out how loud your motor would be without an exhaust tube! The exhaust would be free to spill out the vents in the upper rear of the lower unit. With an exhaust tube, it'll all go down thru the gearcase and out the prop.

I have a feeling your motor will gain a lot of low-end and midrange response with the tuner, although I bet it runs like a Bat from Hades without!

There should be no reason why you couldn't find an exhaust tuner which would fit the center section and exhaust tube, since they obviously exist as well.

It does look like the part may be specific to the 1250, 'cause I looked up gaskets & tuner plates for early models 1150 and 1350, and they were different part numbers.

HTH & G'luck with the parts search.............ed
 
H

Hydro Mark

Seaman
Joined
Mar 30, 2013
Messages
56
Re: Inline 6 Exhaust Tube Installation

Thanks guys. I'm afraid that the drive shaft housing may be different as well. There are two different part numbers for them.
 
H

Hydro Mark

Seaman
Joined
Mar 30, 2013
Messages
56
Re: Inline 6 Exhaust Tube Installation

Mystery solved (mostly)....

Well, it turns out that my '68 1250 did not come with an exhaust tube. This was verified by a forum member with a factory parts manual. Have not determined if it's all 68's or just some of them. In any case, I'm putting her back together. I will try to find out if my housing will accept the tube setup.

Thanks for the help guys.

Mark
 
H

Hydro Mark

Seaman
Joined
Mar 30, 2013
Messages
56
Re: Inline 6 Exhaust Tube Installation

Mystery solved (mostly)....

Well, it turns out that my '68 1250 did not come with an exhaust tube. This was verified by a forum member with a factory parts manual. Have not determined if it's all 68's or just some of them. In any case, I'm putting her back together. I will try to find out if my housing will accept the tube setup.

Thanks for the help guys.

Mark
 
You must log in or register to reply here.
Top