"71" Sears 3 hp ob lu

[tuhuna]

A friend of mine recently resurrected a sears 3 hp ob, runs great. The question is does the lower unit use 90w oil or is it a grease. Thanks for any advice, and that was a great debate on the spark plug issue. T

 

[JB]

Re: "71" Sears 3 hp ob lu

90W is frequently referred to as grease. Usually a heavy lubricant that is pumped to the lubricated surfaces, then recycled is called oil; If it passively wets the lubricated surfaces then it ia called grease.<br />With a few exceptions for special applications (hydro-electric shift) OB lower units use 90W lubricant specified for that purpose.<br /><br />Red sky at night.....<br />JB

 

[tuhuna]

Re: "71" Sears 3 hp ob lu

Thanks JB, Jim told me that when he went to drain the l.u. a very little amount of oil came out but inside it looked like it was packed with grease. I think its been there for some time. thanks again T

 

[Yepblaze]

Re: "71" Sears 3 hp ob lu

You can just leave the grease in there and top it off with gear oil without any problem. Although It is not generally accepted to mix lubricants, under this cir***stance I don't see it being a problem, and the gloop will stay put well if your seals are less than perfect. On some of the old early fifties and older stuff they liked to use grease but that was back then.