Seal(s) Replacement on 1979 Mercury 115 I-6

teewhy

Cadet
Joined
Oct 31, 2002
Messages
23
Once again, I turn the trusting advice and instruction of the Iboats forum to help with a maintenance/repair issue (past threads have proven invaluable). My newest 'project' involves the restoration of a '79 Glastron CVX-16 and '79 Merc 115 I-6. Little history . . .

I purchased the boat as a restoration project and have spent the past year tearing-down the boat, replacing the floors, transom, and re-gelcoating the entire hull. I first de-rigged and removed the motor from the boat and mounted it on a stand (trimmed in) in the garage while I focused my attention on the boat. Now that the boat is in the final stages of work, I'm just about set to move-on to the motor.

Although I've done the intial compression checks (all ok), checked for spark, etc., I have never run the motor. I just removed and put on back burner until now. I recently took a closer look at the lower unit and noticed what looks to be oil (looks more like old engine oil than gear lube) seeping out between the lower unit case and the prop. The fluid is not milky, but, since I haven't run the motor, is it safe to assume this seepage is lower unit lube and not some mixture of water oil which I would expect to come through the exhaust via the prop hub?

I haven't pulled the prop to look closer, but, I thought I'd check with the forum to see:

1) Is this a common sign of a failed prop shaft seal(s)?
2) Any special tools required?
3) I've got old manuals, but, is there a post somewhere that would walk me through the procedure?


Thanks, in advance, for any input!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,911
Re: Seal(s) Replacement on 1979 Mercury 115 I-6

Stick a finger in the oil and smell it. If it stinks of sulfur it is gear lube. If it smells like oil, it is residual fuel or fogging oil.

The prop shaft seals are pretty durable. If they are not damaged by fishing line or something else, they hold up pretty well.
 

Scaaty

Vice Admiral
Joined
May 31, 2004
Messages
5,180
Re: Seal(s) Replacement on 1979 Mercury 115 I-6

Probably fine, just unburnt fuel/oil mix that goes out the thru hub exhaust. Go ahead and do a pressure test if ya want, but I'd use it (put a NEW impeller in it just BEFORE ya plan to get it up and running..don't do it now and let it sit for a year and take a set)..then run it in the water for awhile, and drip out a bit..milky, then it needs a look-see. If not, good to go...
 

OldMercsRule

Captain
Joined
Nov 30, 2006
Messages
3,340
Re: Seal(s) Replacement on 1979 Mercury 115 I-6

Probably fine, just unburnt fuel/oil mix that goes out the thru hub exhaust. Go ahead and do a pressure test if ya want, but I'd use it (put a NEW impeller in it just BEFORE ya plan to get it up and running..don't do it now and let it sit for a year and take a set)..then run it in the water for awhile, and drip out a bit..milky, then it needs a look-see. If not, good to go...

N' that great advice is from a feller who likes ta tear stuff apart fer sport! Good Post. JR
 

Scaaty

Vice Admiral
Joined
May 31, 2004
Messages
5,180
Re: Seal(s) Replacement on 1979 Mercury 115 I-6

N' that great advice is from a feller who likes ta tear stuff apart fer sport! Good Post. JR
Nah, its just that lower units are ...well...boring...I need to finger something with PISTONS!:eek::D
 

teewhy

Cadet
Joined
Oct 31, 2002
Messages
23
Re: Seal(s) Replacement on 1979 Mercury 115 I-6

Thanks all for the helpful insight! I'll go 'head and install a new water pump kit (upper/lower) and go from there hoping that all's well when I take it to the test tank. You'll be the first to know how it goes if you see me on here asking how to change out the prop seals. : ) Thanks again!
 

quebec#1

Petty Officer 1st Class
Joined
Apr 17, 2004
Messages
226
Re: Seal(s) Replacement on 1979 Mercury 115 I-6

Im sure its just fogging oil.
Teewhy can you post some pics of your cvx 16 ? Or email me a few ? I just bought one a 1986 3 weeks ago.
 

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