Why add L/U oil from the bottom drain plug?

[Chaz1]

Why is it that you fill the lower unit from the drain plug hole. Seems to me you could refill the unit from the upper plug just as easy. Any help is appreciated. Chuck

 

[Gary H NC]

Re: Why add L/U oil from the bottom drain plug?

Nope,fill it from the bottom to push the air out the top.

 

[patrick4266]

Re: Why add L/U oil from the bottom drain plug?

it helps in keeping air from being in the lower unit

 

[F_R]

Re: Why add L/U oil from the bottom drain plug?

You can put it in from the top if you want to dribble it in a drop at a time. Otherwise it air bubbles right back out. I've got better thing to do with my time.

 

[Chaz1]

Re: Why add L/U oil from the bottom drain plug?

You can put it in from the top if you want to dribble it in a drop at a time. Otherwise it air bubbles right back out. I've got better thing to do with my time.

I hear ya'! Hey thanks guys. Makes sense.

 

[Dhadley]

Re: Why add L/U oil from the bottom drain plug?

(Watch this.....)

Unless you have a Cobra drive. Then you drain from the bottom and fill from the middle until it comes out the top hole.

 

[Gary H NC]

Re: Why add L/U oil from the bottom drain plug?

(Watch this.....)

Unless you have a Cobra drive. Then you drain from the bottom and fill from the middle until it comes out the top hole.

.......he!he!

Ok Dhadley..LOL..Shame on you!

I can't find my middle hole???

 

[jay_merrill]

Re: Why add L/U oil from the bottom drain plug?

The hole is for venting for both draining and filling. Think in terms of trying to empty a gas can that has no vent hole - it just doesn't work very well. Also, when you finish filling the gearcase, insert the top plug first. The vacuum created by closing the vent will make oil loss from the bottom hole minimal, when you remove the oil line and replace it with the bottom plug.

 

[Chaz1]

Re: Why add L/U oil from the bottom drain plug?

The hole is for venting for both draining and filling. Think in terms of trying to empty a gas can that has no vent hole - it just doesn't work very well. Also, when you finish filling the gearcase, insert the top plug first. The vacuum created by closing the vent will make oil loss from the bottom hole minimal, when you remove the oil line and replace it with the bottom plug.

Yeah I had figured that. Thanks. By the way Jay, pulled my boat out of storage did some maintenance and the old '72 65hp Johnson fired right up! Music to my ears.

 

[Dhadley]

Re: Why add L/U oil from the bottom drain plug?

.......he!he!

Ok Dhadley..LOL..Shame on you!

I can't find my middle hole???

Lol! Someone with a Cobra outdrive will know what I mean. They have 3 holes.

 

[Gary H NC]

Re: Why add L/U oil from the bottom drain plug?

Lol! Someone with a Cobra outdrive will know what I mean. They have 3 holes.

Yea,I know.I used to have a Cobra...
I was waiting for the outboard only guys to get confused...

 

[jay_merrill]

Re: Why add L/U oil from the bottom drain plug?

Yeah I had figured that. Thanks. By the way Jay, pulled my boat out of storage did some maintenance and the old '72 65hp Johnson fired right up! Music to my ears.

Great! Mine does too - I'm usually out in it a couple of times a week and it has really given me good service. Don't forget to put a "Type C" equivalent oil in that gearcase!

 

[Chaz1]

Re: Why add L/U oil from the bottom drain plug?

Great! Mine does too - I'm usually out in it a couple of times a week and it has really given me good service. Don't forget to put a "Type C" equivalent oil in that gearcase!

Yep, I'm all set there. Found the Johnson brand oil at a local shop.