OMC Cobra gear lube top off.

Donzi GT250

Petty Officer 2nd Class
Joined
Apr 22, 2011
Messages
110
I just changed the gear lube in my 1989 5.7 cobra drive.
I followed the manual instructions by refilling the drive from the center plug.
I installed 64 oz's of lube but in the process of getting the center plug back in I lost approx. 2 or 3 oz's. even at that the fill level showed up to the full mark.
After running the engine for 10 min's and letting it sit over night to let the lube settle and work out any air bubbles.
The level is just a bit low as it touches the dipstick but isn't to the full mark.
In this situation I can't see any reason not to top it off through the top dipstick hole as I can't imagine it would take any more that a couple oz's and any air in the lube should be worked out.
So what to you experts think, is it OK to top off through the dipstick hole in this situation?
Thanks
 

DBreskin

Senior Chief Petty Officer
Joined
Oct 20, 2009
Messages
799
Re: OMC Cobra gear lube top off.

Topping it of through the dipstick hole is the correct procedure.

If you use the correct OMC-specified procedure to fill your drive you shouldn't lose any fluid through the fill hole. You're supposed to fill the drive; screw in the dipstick plug, and then remove the fill hose to replace the fill plug. Screwing in the dipstick creates an air lock and will hold the fluid in the drive while you replace the fill plug.
 

Donzi GT250

Petty Officer 2nd Class
Joined
Apr 22, 2011
Messages
110
Re: OMC Cobra gear lube top off.

Thanks for the quick reply.
Yeah I did screw in the dipstick before removing my fill pump from the fill hole.
But in the process of installing the fill hole plug I dropped the plug and gasket so in the time it took me to find the gasket and wipe the dirt from the plug and gasket I lost a couple oz's.
Even with the dipstick tightened down will lube will still kind of flow from the fill plug until you get the fill plug installed ?
 

Joshua Nichols

Lieutenant
Joined
Jun 29, 2009
Messages
1,431
Re: OMC Cobra gear lube top off.

Get you a little funnel and add a couple of ounces to the top
 

Donzi GT250

Petty Officer 2nd Class
Joined
Apr 22, 2011
Messages
110
Re: OMC Cobra gear lube top off.

Another question.
I noticed the part number for the drain plug and the fill plug are different.
When I was changing my lube i didn't notice any difference between the two.
Can anybody tell me what the difference is?
And how ca I tell if i have the correct plug in the correct hole?
Thanks
 

Stanp1

Seaman Apprentice
Joined
Aug 31, 2009
Messages
39
Re: OMC Cobra gear lube top off.

the bottom drain plug should have a magnet either protruding into the fluid of flush on the back of the plug. either way, as long as there is a magnet pulling loose metal out of the fluid, and the plugs don't leak, your fine.
 
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