lower gear oil 1958 johnson 7.5 hp. AD 12 short shaft

[SPK]

Hi again,
I was wondering if someone could tell me what type of gear oil to use in the lower leg of the 1958 Johnson 7.5 and what the capacity would be[i.e how much grease does it hold?] I do have a parts manual but have not purchased an owners manual as of yet so I don't know how much greaseto buy. I have a pretty goog idea of how to change it from referencing the Old Outboard Motor Book.
Any help and ideas would be greatly appreciated.
Thanks,
Sean.

 

[nwcove]

Re: lower gear oil 1958 johnson 7.5 hp. AD 12 short shaft

do a search in this forum......"80w90 automotive". if that dont confuse you, ya cant be confused. with that being said, after you read the thread, buy your preferred gear oil, remove the top and bottom drain plugs and fill from the bottom (it pushes the air out). both plugs are slotted screws. DO NOT remove the phillips head screw.....if there is one on your lower end....it has nothing to do with the gear oil! get some new washers for the drain plugs, they are very cheap !

 

[SPK]

Re: lower gear oil 1958 johnson 7.5 hp. AD 12 short shaft

Thankyou very much for the info. I had read somewhere that 80w90 was a possible choice. I don't suppose you know the capacity of gearcase oil my motor would hold? Will the old gearcase oil drain out on its own[over a period of time] or will it need to be flushed out? If so, how do you do that?Never done one before.
Thanks,
Sean.

 

[lindy46]

Re: lower gear oil 1958 johnson 7.5 hp. AD 12 short shaft

You can get marine gear lube at any Outboard dealer or Walmart has it. Use marine lube as it has additives to emulsify any water that may get in there. A quart is more than enough for that motor. Old gear oil will not drain out by itself, unless there is a drastic leak in the seals. Just remove the drain bolt and vent bolt and let it drain out. Then pump in the new oil from the bottom hole until it overflows the top hole. Replace the two bolts (with new washers) and you're done.

 

[nwcove]

Re: lower gear oil 1958 johnson 7.5 hp. AD 12 short shaft

old gear oil doesnt need to be flushed, it will drain. i think lindy46 misread your question, and thought you had a leak from the lower unit.