View Full Version : 50 HP Merc tiller what weight lower unit oil for winterizing
ohdaddy
11-17-2002, 07:15 PM
First time winterizing. I have a '98 Mercury 50 HP tiller. What is the correct weight motor oil that I should use? Brand? Synthetic?
Thanks
David/MN
11-17-2002, 07:24 PM
That motor requires Merc Premium blend lower unit lube. It's about $6-7 a quart. I believe you need about 12oz.
dw
I just replace the lower oil on my 50 Merc with Pennzoil 75W-90. You can get 2 changes out of a Qt. Also, get a pump it will make the job a lot easier.
perchjerker
11-18-2002, 01:01 PM
Whatever you do, make sure you use oil designed for lower units. It has additives such as anti foaming agents that standard gear oil may or may not have.
erico
11-18-2002, 02:51 PM
Because I plead ignorance, how does the regular Penzoil gear lube behave differently in a lower unit versus say a tractor gear case? If it foams in one, why not the other, and what is the consequence of foaming?
perchjerker
11-18-2002, 02:58 PM
Couple things. Foaming may build up pressure because the lower unit isnt vented. Also, foaming can cause the oil not to adhere to the gears well.
There is some info on the Pennzoil site about it.
http://www.pennzoil.com/penn/products/watercraft/pdfs/special/PennzoilMarinePowertrainLubricants.pdf
The Pennzoil I mentioned is the synthetic marine gear lube. Also, get a pump it make the job much easier. ;)
perchjerker
11-19-2002, 10:34 AM
Good deal, Chad!
Just did my 50 Merc.It takes approximately 14.68 oz.(service manual)I used Quiksilver Mercury premium lower unit lube 3.99 per 10 oz tube,used about a tube an a half.
Some people change it to store their boat and then change it again in the spring before actually using it. If this is your plan use some inexpensive gear lube. I like Lubrimatic Syn. for regular use in the lower unit.