79 140 Johnson

[DavidKnapp]

Hoping for advise new to outboards.
Got oil leaking from behind the prop is there a seal that I can replace?
Is there a spec on the torq that the nut needs to go back on after the prop.

 

[daselbee]

Re: 79 140 Johnson

Yes, you can certainly re-seal the gearcase.

It does take a special puller, and there are 4 bolts way down inside (look in after you get the prop off) that are difficult to R&R.
Then, you should really pressure test it to make sure it is not leaking.

But it can be done.

There could be a different possibility. The oil you see might be black unburned fuel/oil leaking out.

Best to determine if it is gear oil, or that unburned fuel.

 

[DavidKnapp]

Re: 79 140 Johnson

Thanks for advise I will make sure it's oil before I tear into it .

 

[emdsapmgr]

Re: 79 140 Johnson

You may find two types of oil "leaks" around the lower unit. If the oil is a black, tarry substance, that is unburned fuel/oil which is dripping down the inside of the midsection. This is normal and is not a problem. If you find a either a clear, caramel, or blue-green oil leaking down, that is surely gear oil from the geabox. That would be a problem. As daselbee indictates, it's best to do a pressure and a vacuum test on the lower unit to determine if it is actually leaking. Potential seal leaks on that lower unit are: dual propshaft seals, carrier oring, shift rod oring, drive shaft seal. The seal kit you need is: 5000411. It will have extra seals, o-rings in the package since the kit is a universal kit. Basically, the props should be tight on the propshaft. Hard to put a torque spec on the propnut, since the nut is a castle nut and has to be positioned so that the cotter pin goes through the hole in the propshaft. You may have to back off on the torque to get that pin through.

 

[DavidKnapp]

Re: 79 140 Johnson

Thanks emdsapmgr for the information,the seepage is right behind the prop is is black not very thick ,I'm going to drain the lower unit to change the oil make sure it's not contaminated is there s special way I need to do this and ,any lower unit oil will work on the Johnson motors .

 

[emdsapmgr]

Re: 79 140 Johnson

Draining and refilling the lower unit is a good annual preventitive maint. item. You will learn a lot about the lower unit when you change the oil. (is the oil burned?, was the lower unit oil contaminated with any water?, was the lower unit full of oil when you drained it?, any metal chips on the lower drain screw magnet.....) That lower unit oil is a special marine type oil. You will want to make sure you use the proper marine grade of oil-automotive oil just won't work.

 

[DavidKnapp]

Re: 79 140 Johnson

Thanks a million ,you been very helpful emdsapmgr .