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1998 BF90 Lower Unit Gear oil type?

E

Embarq82

Member
From what I understand the 1998 lower is a Mercury unit, assuming the motor I just bought has the original unit... I know Honda lowers are pretty finicky about the gear oil type. Is this the correct Honda hypoid gear oil https://www.ebay.com/itm/2925217080...cSi5BGjTtOuwlomlByohBseHysqViSVIaAnT-EALw_wcB
and would it be ok if I do in fact have the older Mercury unit? and would using the Quiksilver type hurt it if it was the newer Honda unit?


Thanks
Andrew
 
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I've got a 1997 BF90A and I just filled the foot with Mercury Quick Silver 90wt. gear oil (NOT the 80/90wt. which they say is only good up to 75 hp.). You can get the gear oil at Walmart. I believe the foot is identical to a 1997 (in my case) 1998 (in your case) Mercury Force. The parts are identical at least. Also, if you ever need a clutch, people will tell you that there are none left in the universe! Write down this number - 52-822539T there's a guy who sells made in USA aftermarket versions of this clutch and it is IDENTICAL to the existing clutch. The reason I'm so animated about this is that everyone insisted it was time to scrap the motor! I rebuild the foot (gears, clutch, shift rod assembly, and seals and now it runs like a champ! The only way I was able to find the clutch was to look for ones that seemed similar and take a chance.
 
I get motors like that all the time - cheap! A dealer convinces an owner the motor will be too expensive to fix, which, roughly translated, means he has no experienced mechanics to work on it - OR - he'd much rather suck you in to the purchase of another motor.

As far as which oil, I use a synthetic, and believe it's way more important to make sure it's clean w/no water than it is to worry about what brand you're using....
 
Thanks for great replies. That is good to know about the clutch if I ever need that in the future. - which leads to my next question - does a newer model BF90 lower unit work on a 1998 motor?
 
97 and 98 are different than the newer ones. You can look at the pump and see it uses a metal housing where the later are plastic, or you can look at the bolt location for the trim fin. 97/98 have that bolt on top, where the later ones are installed from the bottom. No parts interchangeability, nor can you substitute one for the other.
 
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