re-filling outboard gearbox ?

[redxpuser]

Hi everyone,
i recently purchased a second hand gearbox for my mercury 20hp outboard. As it was posted to me, the gearbox oil had been drained .
I just wondered if anyone could guide me with re-filling this box as I have now fitted a new impellor and fitted the box back onto the leg.
Is there a proper procedure to follow, and please advise type of oil needed (i.e. will proprietry motor oil do ?)

Thanks for any help,

Andy

[m chappelow]

Best way to fill it is to take your time ,,remove/unscrew both the drain and top level plugs,if you buy the proper marine outboard gear oil from a marine.boat dealer it will have a short nozzle/tube ,,push it into the lower.drain hole and squeeze until it dribbles out of the upperlevel hole ,screw in the top level plug ,then the bottom one ,,,,if you try fill from the top plug it takes forever owing to bubbles getting in the way ,,its not a bad idea once filled to turn the propshaft over a few times to reliese any trapped air bubbles caught up in the gears then wait and check the level again a while later as you may find that the true level will drop a bit owing to air bubbles floating to the top .i have used normal gear oil but outboard marine grades better as its supposed to have anti corrosion additives ect .though suppose that if you compare the cost of normal motor gear oil to recomended outboard stuff ,,you could change the normal stuff car more often you may find its ok ,its if you get any moisture through say a leaking seal that the marine stuffs better if left for a long time .

[redxpuser]

Thanks for that, I think I will go and get the proper oil, as I don't know which grade to use !

Thanks again,

Andy

[m chappelow]

Originally Posted by redxpuser

Thanks for that, I think I will go and get the proper oil, as I don't know which grade to use !

Thanks again,

Andy

best you use the marine stuff , the grade is normally 80,,90 grade

[Searider]

If you want an easy life both Quicksilver and Yamaha do a pump which you can fit to their litre bottles of oil. This has an adaptor which screws into the drain fitting. Pump the oil in, replace the upper plug, remove pipe, replace drain plug.

Costs about £15.

The small tubes of oil (300ml?) cost about £8
Litre bottles about £17

Pump and a larger bottle cheaper in the long run. No mess either!

[jyasaki]

If it's a small motor, the pump may be overkill. A small lower unit won't hold a bunch of oil. A couple of tubes should work fine, and aren't that much messier.

Couple of tips: 1. have a rag or two handy for wiping up drips before they fall off the LU. 2. Rubber band or tape a wad of paper towel or rag around the LU below the drain plug (the lower screw.) 3. A small box or similar makes it easy to put down the oil container without having to worry so much about spills. 4) A burst of carburetor cleaner to the plugged, uh, plug will clean away any remaining oil, making it easier to detect a leak (rather than indicating a leak when there isn't one.)

jky

[redxpuser]

Thanks for that, will do the job at the weekend,
Andy