How much gear oil is ok to loose when changing lower unit?

[camawelander]

Hello,
I am wondering how much Lower Unit Oil is ok to loose when doing the oil change. No matter what, I tighten the upper vent hole, and then quickly pull out oil bottle nipple and replace the lower screw, I am loosing some oil. Is this to be expected?

1989 Force 35

 

[racer-x]

Re: How much gear oil is ok to loose when changing lower unit?

Lower screw as in drain screw? I would say that there is an upper screw marked FILL that you should be using, beside the VENT screw.
When I pull the bottle out, a little comes out but certainly not enough to worry about. I give a little squeeze, block the hole with my finger, get the screw ready to go and a few seconds later it's a done deal.

 

[fishrdan]

Re: How much gear oil is ok to loose when changing lower unit?

I 'll second racer-x's method, works good.

If your worried about loosing too much fluid while inserting the lower screw, just remove the top screw again to check the fluid level and add a bit of fluid if necessary.

 

[camawelander]

Re: How much gear oil is ok to loose when changing lower unit?

On this 89 Force 35, there is only one upper screw and it is labled "Vent". I have changed the oil a few times using this screw, does anyone know if this is the proper method?
....So it is acceptable to loose a small amount of oil when replacing the drain plug....thus leaving some air in the lower gear case?

 

[roscoe]

Re: How much gear oil is ok to loose when changing lower unit?

35 horse only has a vent screw at the top, and a fill screw at the bottom.

camawelander, you appear to be doing it correctly.

Common to lose up to an ounce of lube.

Make sure you are using new gaskets on those 2 screws, every time you change it.

Happy boating.