Is there any reason not to use a good 80-90w GL-5 gear oil instead of the "MARINE" lower unit oil. The specs I have seen (both are GL-5), and the people I've talked to, seem to believe they are the same. Any input? Thanks
I once looked at the actual specification sheet on Lubramatic 90wt. for both marine and ag. There was no difference. It worked fine. This was about four years ago. Then I got to thinking ...I use so little of the stuff why not go marine. So I did. I personally feel there is no difference. I like to hear the 'real story' from somebody out there.
the marine stuff is made to be in waterlonger. and water will float to the top and not couse harm. on some other stuff water will mix and form bubbles. try using corn oil in there (did that ti see what would happen) it turned to a true solid (it was at chease density)!!!
Well I'm going to get an answer for all on this subject. I will have a test done with someone at an oil company. (Engineer Lubricants) They will do a test and determine if there is any differences. I will get back in a week or so with the results.
A few years back I had a 1958 mercury Mark 35ae. It had a bad seal below the water pump cartridge which to replace could very easily destroy the water pump housing and or cause problems with the lower unit housing during the process. (as I was told by more than one)So anyway, I used to change out the gear oil quite often. I would run it and within 1-3 days afterwards I would have it changed out again. The warmer the weather the faster the water would settle out.<br /><br />I preffered the oils that would seperate well allowing the water to be first out. It also would mean the water was expelled and not still in emulsified form to seperate later from residual.<br /><br />My oil of choice was Walmart Supertech 80-90 plain old gear oil.<br /><br />Upon trying the marine varieties I found they held the water in suspension longer.<br /><br />Also the lower unit had some other problems and it wouldn't catch reverse well. It took a carefull hand to hit reverse just deep enough to grab the gear without going "past" it. I also found during these time that the cheapie standard 80-90 outperformed the marine variety hands down in it's ability to hold onto a less than perfect gear engagement.<br /><br />Ran that sucker for 4 years like that probably 100 days a year. The lower unit never let go or became worse from it.<br />
Well without doing any test, my friend who is a chemist with a lubrication company did explain the differences. Some of you guys hit the nail on the head. The MARINE stuff has emulsifiers in it. This will allow the water to mix with the oil if it gets in. Without it, the water would settle to the bottom, where you need the lube. If anyone knows anything about machining, it would be like a water soluble coolant. Later.
