OMC Cobra drive oil dirty

[av8or09]

I was doing my pre-summer maintenance on my boat ( oil change, grease, fuel filter, etc...) when I checked the outdrive lube oil level I also drained a small amount from the bottom drain to check for water or other contaminants. What I found was the drive oil was realy dark even though it appeared to not have any water or other visible contaminants and it did not smell burned. You can see a slight gold tint ( as in copper or brass in the oil). I only have about thirty hrs on the upper and all new bearings in the lower. The drive gears and dog clutch were like new so I only replaced the bearings , thrust washers, seals, etc.. I pressure and vaccuum tested to OMC specs. I also used original OMC HI-VIS gear oil (PRICY!!) but considering I just spent 1,000.00 plus I figured it was cheap insurance. The problem is now I am worried about running it as is. The level was normal when I checked and yes I did fill it properly and checked the level EVERYTIME we used the boat to be safe. I also replaced the drive bellows and sealed it per the OMC manual so I dont think water is the problem. ALso it should not be a shift problem causing gear wear, I replaced shift cables and adjusted shift linkage per specs and it shifts with one finger and no clunk going in or out of gear. Normal idle also. What else could discolor the oil to that extent and is there a way to flush the old oil out and replace it without doing any damage to the drive?? THANKS<br /> The boat is a 89 SUNBIRD with a 4.3L/2V cheverot with an OMC COBRA O/D.

 

[dka1ser]

Re: OMC Cobra drive oil dirty

Every time I have replaced the gear oil on my engines its come out black. 10hrs,20hrs, 100hrs a season didn't matter. <br /><br />If you just replaced the bearings and such, that could explain the tint in the oil, a break-in? I recall the same when I gear work done on my old Johnson outboard, the gear oil looking different. <br /><br />My suggestion would simply be to drain it overnight, refill, and see what happens in the next few outings (5hrs), i.e. how quickly it turns black. Just like in a transmission in a car, the black gunk is caked on the walls of the gear box I imagine, and it would require a solvent to flush it out, I'm not sure if it would be worth that to get the gunk out. Like I said before, mine was black pretty much after the first outing everytime, and I never thought twice about the color, since it was i'm sure from the build-up of dirt and such on the non-moving parts. <br /><br />Water turns the oil milky brown colored, so its not water for sure.

 

[Bondo]

Re: OMC Cobra drive oil dirty

Don't Flush It With Solvent.........<br /><br />Any time a pc. of Machinery is rebuilt,.. There's a Run In Time.......Till the 1st Oil Change......<br /><br />Now, How Long,.. Motors,.. I like 10hrs,.. Maybe 20...... Depends on the Conditions.......<br />Outdrives, I'd go about the same.... Some say I change oils Too Often,..... Maybe, But Oil,+ Filters are Cheap.....<br />My engine,+ drive Rarely run more than 50hrs on a change,.. And, That's with SynOil.....<br />100hrs is Much More Common......<br /><br />Anyway,............ In Your Case,...... Everything is Normal,.........<br />Just Change the Oil in the Regular Way,+ Go Boating...................

 

[av8or09]

Re: OMC Cobra drive oil dirty

Thanks for the advice. I will just drain and replace hoping it is just breaking in and nothing else. Drive oil is definitely cheaper than another rebuild!! I am a little obsessed with maintaining the oil level in the drive since I found out what damage is done and the replacement cost of one. THANKS AGAIN!!