Wits End on Lower Unit .Please Help.

[Mercurylips]

I have been carefully rebuilding my lower unit on an older Merc 500. 1977 vintage. I have replaced every seal (some of them twice) and replaced the needed bearings ( all). I have tried to follow the manual (mercury) and done my due diligence but upon checking my gear oil after each usage, I come up with a creamy color for the oil. I have tried pressure testing and can't get it to bubble while submerging it off the motor. Nothing works so far. Last week I took it out and fished with a trolling motor for 3 Hrs All I used the Merc for was idling out and idling in (no wake lake). Still the milky oil. It is winterized now so anything else will just be working with the lower off the motor. This old motor has been challenging and it runs and starts perfectly. Hate to give up on it now. BTW I use Valvoline synthetic blend.

 

[jimmbo]

If new seals aren't sealing, what condition are the shafts in? When pressure testing, have you rotated the driveshaft, the propshaft, and the shiftshaft? Have you done a vacuum test on case?
When installing the seals, are you orienting them correctly?

 

[Faztbullet]

Is that marine oil???? Automotive oil will foam in a non vented gearbox....

 

[Mercurylips]

If new seals aren't sealing, what condition are the shafts in? When pressure testing, have you rotated the driveshaft, the propshaft, and the shiftshaft? Have you done a vacuum test on case?
When installing the seals, are you orienting them correctly?

No vacuum test. All else was done and the propshaft changed. Seals are all done correctly and locktite used.

 

[Mercurylips]

Is that marine oil???? Automotive oil will foam in a non vented gearbox....

​Duh! I just took a better look at my gear oil and there is no mention of marine. This may be why it looks milkey and I never can find water in it after it sits for a week. Ithought it would at least separate in a jar but still no water. Just stays milky. I will ponder this for a while. Recommend oil to use, please. Thanks, Mike

 

[racerone]

Maybe there is a crack in the gearcase ?---Shift rod seal changed ?-----A pressure test will find the leak.----Tiny air bubbles mixed into the oil will make it look milky.

 

[GA_Boater]

What lube are you using?

Go to WallyWorld and get some Quicksilver Gear Lube. The label tells you which one - High Performance for 70 HP and above, Premium for below 70 HP. Use Premium.

 

[Mercurylips]

Maybe there is a crack in the gearcase ?---Shift rod seal changed ?-----A pressure test will find the leak.----Tiny air bubbles mixed into the oil will make it look milky.

​Couldn't find a leak. That's why I was being driven berserk. I am starting to wrap my mind around Fastbullets' question about the oil. I bought what I have used for the past two years from Menards because it was in the marine section. It is clearly not Marine Oil.

 

[merc850]

Did you follow this directive? Perfect Seal is available from Merc and can be used for many applications. Also, did you replace the O-rings on the carrier, the waterpump base and; tork the
nut to 110 ft/lbs?

 

[Mercurylips]

What lube are you using?

Go to WallyWorld and get some Quicksilver Gear Lube. The label tells you which one - High Performance for 70 HP and above, Premium for below 70 HP. Use Premium.

​I will get some Quicksilver Premium. At this point I would be elated if all that is wrong is the wrong oil. The only problem with that is the boat is put up for the winter and I will not get an update out on the problem until late april next year. I will take a mixer on high speed and see if I can get the consistency with my motors gear oil has when it has been used in a lake.Thanks for all the help guys, Mike

 

[Mercurylips]

Did you follow this directive? Perfect Seal is available from Merc and can be used for many applications. Also, did you replace the O-rings on the carrier, the waterpump base and; tork the
nut to 110 ft/lbs?

​I used Permatex sealer. All other directions were followed except I would be some ft lbs higher than 110 on the cover nut since mine is metal and I tightened the poop out of it. Permatex was recommended by a retired Merc mechanic and Perfect seal wasn't available in town. This is pretty much Evinrude country. The only evidence of leaking oil out the propeller area is a tiny gooey black puddle from the exhausts unburned oil that comes out because I lower my motor when it is parked inside after use. This area was to be my next target but as of now, I've decided to see how the proper gear oil works, even if I have to wait till next year. Thanks for the help, Mike

 

[jimmbo]

Permatex3 and Perfect Seal are pretty much the same stuff. Mercury used to recommend it be used on propshaft splines too

 

[Mercurylips]

I'll write an update after I take the foodmixer to the current use oil.. Thanks again.

 

[Mercurylips]

Is that marine oil???? Automotive oil will foam in a non vented gearbox....

​I used my mixer and created a nice Vanilla Shake out of my gear oil in my man cave. I will be off to get some quicksilver and will get more aggressive with this in the spring. I will let my bowl of lube sit for a few days to see what it looks like after settling. It seemed like the stuff I got out of my lower was whiter. Too bad I tossed it and can't compare. "Stupid is as stu......................."!, Mike