Gearbox oil change FAIL!

[Merrie Thames]

Hi

I'm trying to change the gearbox oil on my Tohatsu MFS20. The manual says you have to undo the top and bottom oil reservoir bolts and then squirt the oil in from the bottom hole and stop when it emerges from the top hole.

No matter how hard I try, I can't get it full enough to come out of the top hole, the oil just won't go in, like there's a massive airlock.

Has anyone got any tips?

[Nos4r2]

Buy a gear oil pump It makes it very very easy.

[jyasaki]

The stuff is thick, but it does go in. Maybe opening up the nozzle on the tube a bit more?

Easiest way (assuming you can find the parts - it can be tough sometimes) is a pump, as Nos said, plus a threaded hose that screws into the bottom plug hole. The fitting that screws into the leg can be tough to find.

That said, if the old oil drained out pretty easily, then there should be no blockage issue. Have you tried pouring some gear oil in the top and see if it runs out the bottom?


jky

Worst case work-around: you *can* fill from the top, but you need to work the oil around and give it time to get all the air bubbles out. Takes a lot longer. Make sure the leg takes the approximate amount that the specs say it should.

[Hightower]

I would look at extending the fill tube from the bottom hole so that you can raise this above the level of the top hole. That way gavity will give you a helping hand my friend

[jezza2011]

Yep buy the gear oil pump that screws in to the lower plug hole and on to a gear oil bottle.
Checked and refilled mine today. took about 5 mins tops ;-0

[Scrottocks]

Get a length, about 4 to 5 feet, of transparent polythene tubing (like beer brewers use) which is a tight fit in the lower (drain) hole plus a funnel which is also a tight fit in/around the tubing.

Support the upper end of the tubing/funnel above the engine with the lower end stuffed in the drain hole. Fill funnel with oil. Wait. Keep checking every five minutes as the oil descends into the gearbox.

Eventually oil will appear from the upper hole. Put in upper plug, pull out the tubing and insert lower plug.

All done with you standing upright and hands-free instead of crouching at gearbox level and squeezing an oil bottle 'til your hands hurt.

Simples!

[skiffed]

Try putting it in the right hole. That is the one just above the skeg not the higher one below the top hole where I was trying to put it with a squeeze bottle and multi grips without success. In the right hole with the squeeze bottle and a gentle squeeze it was as easy as could be. Maybe fifteen seconds at most. Also easier if you tilt the motor and turn. That way you can get the nozzle in easier.

[hobbit555]

Warm the oil in a pot of boiling water

[Max...]

Buy a *big* syringe on eBay, job is a cinch - remove both plugs, squirt syringe into bottom hole then stick finger over top hole to create air lock and oil coming back out. Screw bottom plug in a little, refill syringe and finger back on top remove bottom plug again, insert syringe and repeat until oil emerges from top, finger on top hole, syringe out and bottom plug back in. Lot simpler and quicker in practise than describing!

[Nos4r2]

Why make it so bloody hard? The pump is a few quid and makes practically no mess....

[martini]

On the subject of pumps, does anyone know of a good after market one? I've got a quicksilver that screws into a 1 litre bottle but it's not very good, pumps really slow.

[uncle al]

use a pump that screws onto the gear oil bottle, thats all i used and i went all over the U.K. servicing/repairing H.M.C.G. obms a few years ago, a piece of cake