1996 M40C lower unit shift shaft seal replacement

[mudchuck]

Hi all!
I bought a seal kit for this motor, and a water pump kit.
I've got copies of the service manual and parts lists.
Was hoping one of you seasoned repair salts could guide me on the seal kit work, as not much info to go on looking thru You Tube or other forums on what's involved with replacing the seals on this motor's lower unit.
Water pump kit is pretty straightforward, but I'm a little intimidated about the seal kit with the oil seals, especially the shift shaft seal.
Anyone out there that can offer some pointers or perhaps a set by step guide to doing this work it would be greatly appreciated.

~Mudchuck

 

[pvanv]

Not a lot of seals. Of course the prop shaft housing o-ring, and the o-ring under the water pump, plus the drive shaft and prop shaft seals. The most overlooked items are the o-rings for the cam rod bushing. The inner one can be a little tricky, but I use a dental pick to pull the old one, and a blunt punch to install the new one.

 

[mudchuck]

Thanks Paul, kits arrived and planning on tackling this over this Labor Day weekend.
If you have any pics of the shaft shift seal or cam rod bushing when you did yours please share.

 

[pvanv]

Just follow the parts catalog.

 

[mudchuck]

Paul, I'm reviewing what comes in the lower unit seal & the water pump kits.

The water pump kit is a no brainer, it has these:
(14-14) 345-65021-0 impeller
(14-16) 348-65011-0 pump case liner


(14-20) 348-65025-0 water pump guide plate
(14-21) 348-65029-1 pump guide plate gasket (which also comes in the lower unit seal kit)
(14-22) 348-65018-0 pump case gasket (which also comes in the lower unit seal kit)
(14-24) 910103-5652 x4 bolt & washer set



The lower unit gasket kit came with these:
(14-18) 345-60111-0 oil seal
(14-19) 345-65015-0 o-ring
(14-21) 348-65029-1 pump guide plate gasket
(14-22) 348-65018-0 pump case gasket
(14-34) 345-66021-0 x2 o-ring for cam rod bushing
(14-35) 332-66032-0 o-ring for cam rod bushing
(15-12) 334-60223-0 oil seal for prop shaft housing
(15-14) 345-60103-0 o-ring for bevel gear/bearing


The lower unit seal kit however gives me cause for concern.
What I don't know are what are these fiber washers and small o-ring in the attached picture for?
I cannot locate them on any of the parts catalog breakdowns.




Your insight is appreciated!
~mudchuck

 

[mudchuck]

WOW, that prop shaft seal is very hard to remove!
I've buggered it up trying to get it out and afraid I need to find a machine shop that can remove it and press the replacement in.

 

[pvanv]

The fiber washers are for the drain screws. The o-ring is probably for the cam rod bushing. I drive the prop shaft seals out with a punch, and install in a vise with a socket as a ram.

 

[mudchuck]

Paul, I was able to find a shop that could get the prop shaft seal off and press the replacement in, didn't even charge me for it!
The old seal was incredibly corroded. Motor was originally from NJ, and in saltwater. Lots of built up salt deposits, and a load of very old mono.
It was certainly the original shaft seal.

I've gotten thru all the seals & gaskets except the cam rod bushing...no idea how to get down in there to the bushing...any suggestions?

 

[mudchuck]

And the bad news, after all that work it still leaks gear oil out the same weep hole.
running it on muffs i see exhaust puffs coming out that weep hole too.

 

[Sea Rider]

Have you done a pressure test after gear box was serviced ? will tell if will have oil leaks afterwords. There are small side holes located on lower leg, it's normal to see some form of unburned 2 strokes remains going down through exhaust if that worries you. If found there's new gear oil leaking through lower leg it's a different story.

If you have found large salt deposits on lower leg, imagine how much salt build ups will have inside the entire powerhead. Fill a barrel with water, add Salt Away product, remove thermo, bolt cap back alone, run OB-On at idle for say 15-20 minutes for a faster full powerhead clean out.

If current thermo is severely rusted, salted, buy and install a new one along a new thermo gasket. Engine will work and cool much better than before

Happy Boating

 

[pvanv]

There is a stopper screw on the starboard side of the gear case for the cam rod bushing.

 

[mudchuck]

Paul, found the stopper screw gasket, all set there.
Only 2 that didn't get replaced were the cam bushing o-rings. I have no idea how to get down in that cavity to get to them.
Anyhow, all seals except those 2 are inplace, and Sea Rider, I have no thermostat and just let the water run thru the motor without one since I've replaced it a few times and they just stick way too much, and mostly at the most inopportune time.
That said, I figured it wasn't a big deal not having a t-stat in place since water needs to run thru it and cool the motor.
I suppose the side effect I'm seeing of not having a stat is the engine doesn't warm up enough to burn off the fuel mix and the small amount of oil at the lowest weep hole is unburnt fuel mix.
Since I only muff tested the motor yesterday after the seals being replaced, I probably didn't run the motor long enough to properly warm up.
There's no water in what is weeping out the lowest drain hole so far since I replace the seals yesterday, and the tiny amount that I did see never increased in volume overnight. It also doesn't stink like gear oil but rather has a mild smell.
My fingers are crossed that I did a good job...
If the wind would die down enough I'd get it out on the loake, but way too windy and heavy rollers yesterday & today and forecast this afternoon thru tomorrow is about the same...guess I'll have to wait.

 

[pvanv]

After the screw is out, you just pull up on the cam rod, and it all comes out.