Thoughts on cornhead grease?

[Carver121]

So I have an old 1970 mercury 110 9.8 that I've replaced the shift shaft and driveshaft seals on. Went out a couple times and now I see its leaking out the exhaust again.....

The driveshaft did worry me as it looked a bit corroded so I wasn't sure how it would hold out.

I've seen people talk about using cornhead grease in leaky gearboxes and that antique outboards used grease instead of oil.

Is this a viable solution? we don't run it all day, just out to our spot and then we run the electric anyway. I would like to get a couple more seasons on it if possible, and otherwise it runs great.

 

[tpenfield]

The earlier Mercury outboards (up until about 1978-'79) had carbon steel drive shafts, which would start to pit and loose the oil seal. The water pump, being right on top of the seal would pull oil into the cooling system and out the exhaust.

Not sure if grease would do the job, or result in other problems because the driveshaft seal will quickly wear out with a pitted driveshaft.

You can replace the carbon steel drive shaft with the newer stainless steel shafts . . . which I did on my 1969 7.5 hp Merc. The newer driveshafts (1979+ model parts) are scarce and pricey, but if you can find one (eBay) you could 'save' the engine.

 

[Alumarine]

I used Lubriplate 105 in the gear case with a slight leak on an old 9.8.
It's a very thin grease.
I used it for a few years and it worked. It only ran for 1/2 an hour now and then.
Don't have the motor any more so not sure how long it worked.

 

[flyingscott]

Use marine-tex epoxy fill in the gouge and sand it smooth with sandpaper. start with 220 and finish with 1000 grit.

 

[racerone]

If I absolutely needed to save / re-use a rusted shaft I would machine and install a thinwall sleeve.-----Stainless with 0.010" wall thickness.

 

[Faztbullet]

Weld her up and grind it down and polish..preferably a machine shop unless you got a lathe setup

 

[Carver121]

If I absolutely needed to save / re-use a rusted shaft I would machine and install a thinwall sleeve.-----Stainless with 0.010" wall thickness.

I have no great love for this motor, but it runs and is paid for. So all comes down to cost to keep going and I have a feeling that having it sleeved by a machine shop may be more than I choose to spend right now.

 

[Carver121]

I should also add I can only find that shaft seal in a kit for like 70 bucks. Unless I can find it individually fairly cheap I also don't want to throw time and money into an attempted repair on the shaft, replace the seal and still see it fail.

 

[racerone]

Everybody has different methods , standards and reasons.-------That seal should be available for very reasonable if you know how to look for it !!

 

[Texasmark]

I used Lubriplate 105 in the gear case with a slight leak on an old 9.8.
It's a very thin grease.
I used it for a few years and it worked. It only ran for 1/2 an hour now and then.
Don't have the motor any more so not sure how long it worked.

I use Lubriplate 105 (engine rebuilding grease for initial run-in) in my older bush hog type rotary, tractor mounted mowers with a leaking shaft seal. Thick enough to stay in place, thin enough for the rotating gears to sling it out where it's needed. I never used in in a marine gearbox. Only as indicated and those boxes were full at half or less the vertical height of the box. Don't know if there are upper bearing lube and cooling requirements on the top driveshaft bearing that might go lacking with it.

Most any auto parts store carries it in a white tube; turquoise cap.