Pressure test, lower unit seals estimate

[tmcalavy]

Okay guys,<br />My mid-70's Merc 500 50 hp 4 cyl has vanilla milkshake lower unit oil...was hoping new gaskets on vent and fill holes would do...but NO WAY. So, how much can I expect to pay for a pressure test and to replace the seals? Need a price range before I take it to my boat guy. I have a service manual on the way, so if it ain't too hard I may pay for pressure test to confirm and then do seals myself...unless one of you sages recommend otherwise. All replies welcome mates.

 

[petryshyn]

Re: Pressure test, lower unit seals estimate

if it ain't the vent/fill screws, its likely seals. The engine is old.....do all seals and o-rings while you are in there. Don't waste money on a pressure test at this point....

 

[Mumblerone]

Re: Pressure test, lower unit seals estimate

Schematic-I've often wondered. For sake of conversation lets assume water leaks in, oil does not leak out. Water makes the oil milky. How much water do you think it takes to turn oil milky? A given lower unit might have run for years with milky oil. I know it's a risk, but if a motor is not used alot, it might operate just fine with a little water. The point is, it might be OK to just drain and refill the lower unit vs replacing seals. This is ,of course, a personal call. This should be done at the end of the season up north, to prevent water from freezing in the lower unit over the winter, then cracking the lower unit. Given the age of this motor, I would agree with your answer.

 

[tmcalavy]

Re: Pressure test, lower unit seals estimate

Thanks for the quick replies. Now, any guesses as to what these seals/o-rings will cost? Not labor, now. Just the parts. Just need an estimate so I'll know whether I'm getting the slimy shaft.

 

[wilde1j]

Re: Pressure test, lower unit seals estimate

Typically, prop shaft seals. drive shaft seal, shift rod seal and other O-rings and soft parts are less than $50. Labor depends on the specific motor, whether its ever been in salt water (makes it sometimes very hard to remove the bearing carrier) is typically several hours (shop labor is typically ~ $70/hr). You also will need the gearcase refilled with lube, another $5 to $10.<br /><br />Running the motor with water in the gearcase will lead to rust and damage of very expensive parts.<br />Jim

 

[Boatin Bob]

Re: Pressure test, lower unit seals estimate

I didn't see it mentioned but you probably should do the water pump as well

 

[ruel42]

Re: Pressure test, lower unit seals estimate

I just had a 200 merc resealed and spent around $225 which included a water pump.