Changing gear oil - newbie question

[dedrie77]

Hi - first time posting...

I have a 50hp Merc that is about a '99, maybe '98. I need to change the gear oil as I've been running it since last March - it's been about 100 hours. Anybody have a simple step-by-step solution for a newbie?

 

[Gary H NC]

Re: Changing gear oil - newbie question

Stop by any Mercury dealer and pick up a quart of gear lube,new O-ring washers for the vent,fill and drain plugs.(always replace them at every change)
You can get a lube pump for about 6 bucks at Walmart.
Pull the bottom drain screw,the top fill and vent screws and let drain.
Slowly pump the new lube in from the bottom hole until it reaches the top or vent hole.
Put the top plug back in and quickly unscrew the lube pump and put the drain plug back in......
Wipe up the mess and thats pretty much it.

I usually recheck at the top fill plug after a run to make sure its full and any air was in it. It may need a slight top off but usually not.

 

[Rip n Lips]

Re: Changing gear oil - newbie question

And make sure you get the pump, it's a god send...

And don't do it on a windy day

 

[chrishayes]

Re: Changing gear oil - newbie question

Prepare for DA STINK! nothing quite smells like good ol gear oil. good luck, its not hard.

 

[barryll]

Re: Changing gear oil - newbie question

I know this is late but it might help someone else that has the same question.

http://www.youtube.com/watch?v=Wj0la6c5FDg

 

[dedrie77]

Re: Changing gear oil - newbie question

Thanks!! It was much easier than I expected - the oil I bought was in a squeeze tube so I didn't get the pump and it seemed to work out pretty well. We scraped the boat while we waited for it to drain and it runs so well now we can cut our gas usage by a third!

My only question - the guy at the boat shop and someone on this forum said there would be three screws - drain, fill and vent. My 50hp merc (1999) only had two. Could I possibly have missed one?

Thanks again!!

 

[joed]

Re: Changing gear oil - newbie question

I have only ever seen two holes. Drain and fill are the same hole at bottom. Vent at top.

 

[AZcamperguy]

Re: Changing gear oil - newbie question

I have a question regarding this also. The guy in the video says to use plastic or teflon washers because they are better. Where would you find these if the marine shop doesn't have them? Also, what do you guys do with the old gear case oil once you have drained it?

 

[Gary H NC]

Re: Changing gear oil - newbie question

I have a question regarding this also. The guy in the video says to use plastic or teflon washers because they are better. Where would you find these if the marine shop doesn't have them? Also, what do you guys do with the old gear case oil once you have drained it?

Johnson-Evinrude sells the plastic (nylon) washers..
Mercury dealers sell the blue paper type..

I put the old oil in a gallon jug.When it gets full my local parts store accepts waste oil.

 

[AZcamperguy]

Re: Changing gear oil - newbie question

Johnson-Evinrude sells the plastic (nylon) washers..
Mercury dealers sell the blue paper type..

I put the old oil in a gallon jug.When it gets full my local parts store accepts waste oil.

Thanks for the tip. I didn't know that the Johnson ones were interchangeable with the Merc ones.

When you say partss store, you mean auto parts right? I knew they took car oil.

 

[BoobieBouncer]

Re: Changing gear oil - newbie question

My manual says to drain 1 ounce of oil out after filling to account for expansion.

I didn't do this once and blew out the drive shaft oil seals...

 

[AZcamperguy]

Re: Changing gear oil - newbie question

Interesting, I don't recall my manual saying anything about that. I will have another look at it tomorrow.

 

[cell]

Re: Changing gear oil - newbie question

My manual says to drain 1 ounce of oil out after filling to account for expansion.

+1

Everything Ive read says that too.

 

[AZcamperguy]

Re: Changing gear oil - newbie question

Hmmm, it doesn't say anything about it in my manual. I have a Mercury 6 hp 4 stroke. I just checked it again and it just says to replace the vent cap when I see the oil rise to it and then remove the filling tube and replace the drain plug.

 

[BoobieBouncer]

Re: Changing gear oil - newbie question

I have an old 1977 85hp 2-stroke 4 cylinder...

I would give a mercury repair shop to check what you need to do for your engine.

Here's what my manual says:

 

[AZcamperguy]

Re: Changing gear oil - newbie question

That's a good idea BoobieBouncer. I think I will call them before I do it.