1996 15 hp 2 stroke mercury lower unit HELP!!

[huntn100]

Hello Tin Boaters, I am new to this forum and new to outboard repairs. Ive been a auto mechanic for 15 years, so I feel I'm capable of this repair. I have Seloc repair manual but it says nothing about replacing prop shaft seals. My questions are, is there a more complete manual available? How do I know if my motor is threaded or if you have to use a puller to remove the prop shaft and reverse gear?
Thank you all in advance

 

[GYPSY400]

If your just removing the seals near the prop you can do the trick where you put a screw in it to pull out the seal.
Check out Dangar marine on YouTube.
Most likely there are 2 seals back to back... one keeps water out, the other keeps oil in.

Sent from my SM-G960W using Tapatalk

 

[nccatfisher]

To answer you question yes, there are better manuals, OEM. But finding them may be tough. Start on eBay.

 

[Pappy]

Let me ask you a question.
Are you replacing the seals because you are seeing a drip on the garage floor (or wherever you keep it) after the engine has been run and brought back home?
Do yourself a favor and removed the drain plug in the gearcase and let a few drops of gear oil come out. If it is milky then yes you have some water getting in through a seal. If it is black or natural oil colored then what you are seeing on the garage floor is nothing but unburned fuel and oil slowly draining down the inner exhaust housing and dripping out of the gearcase just below the propshaft seals.

 

[huntn100]

I have only had the motor on the water once. I noticed the gear oil/water mix oozing out of one of the holes on the shaft above the lower unit. That was more than a year ago. I drained the gear oil out yesterday (a little nervous what Id find). What came out was a nice clean blue gear oil that looked to be very fresh. when I removed the prop there is oil residue inside, I suspect the seals on the gear carrier assembly, the seals around prop shaft appear in good condition. So maybe that answers your question?

 

[MrGiggles]

I have only had the motor on the water once. I noticed the gear oil/water mix oozing out of one of the holes on the shaft above the lower unit. That was more than a year ago. I drained the gear oil out yesterday (a little nervous what Id find). What came out was a nice clean blue gear oil that looked to be very fresh. when I removed the prop there is oil residue inside, I suspect the seals on the gear carrier assembly, the seals around prop shaft appear in good condition. So maybe that answers your question?

It is pretty unlikely that you would have a failed seal that would let a lot of oil out, but not let water in.

I agree with Pappy, what you are seeing is probably just 2 stroke drool, nothing to be concerned about, they all do it. If the oil is clean and the level is not dropping, run it. Just drop the drain and take a sample periodically between change intervals, like you would with any motor.

You could pressure test the lower unit to further put your mind at ease without taking anything apart, drain the oil and make an adapter for a Mityvac, I'm guessing you already have one. You won't be able to see the leak if it is coming from the drive or shift shaft seals, but it'll tell you if there is one.

 

[huntn100]

Ok! Thank you all very much. I will get it all back together and monitor. Now I can focus on making sure the carb is happy and running like a top. I need to go through the boat as well, it is a 14 ft alumacraft bought new by my Great grandfather. It is the boat I grew up on, fishing with my grandfather, Dad and brother. I am hoping to have it ready for the lakes as soon as the ice melts.

 

[Pappy]

I have only had the motor on the water once. I noticed the gear oil/water mix oozing out of one of the holes on the shaft above the lower unit. That was more than a year ago. I drained the gear oil out yesterday (a little nervous what Id find). What came out was a nice clean blue gear oil that looked to be very fresh. when I removed the prop there is oil residue inside, I suspect the seals on the gear carrier assembly, the seals around prop shaft appear in good condition. So maybe that answers your question?

Re-read the last sentence of my post. This subject has been covered in here a myriad of times so far. you can probably search it if you want to.
When you pulled the prop that is exactly where you will see it. You can also smell the residue and verify it is unburned fuel/oil

 

[huntn100]

Thank you all again for the advice and direction. I confirmed it is not the lower unit(thank goodness). I was able to pull the lower unit shortly after running the motor and seeing the oil foam appear. The gear oil was clean and I was able to look up into the exhaust housing, It is definitely coming from the exhaust. It is a relief to know that there is nothing majorly wrong with this motor and I can now turn my focus on the boat.

 

[huntn100]

Oh, and I had attempted a search but because I had incorrectly been so focused on the lower unit I wasnt able to find what I needed. In a way I was ignoring anything with the motor or exhaust because I convinced myself it was in the lower unit. So thank you for steering me in the right direction

 

[nccatfisher]

It is what is commonly known as two stroke slobber.

 

[huntn100]

Its pretty gross.

 

[CedarRiverScooter]

I put a pc of cardboard under LU when I park my boat after an outing. Otherwise have an oil spot.