165hp OMC I/O Gear box leak?

[DukesFin]

I've got a 165hp OMC I/0. I noticed "creamy" oil in the bilge. Engine oil level is not going down. I'm thinking it is the gear box. Any suggestions? While I wait on my shop manual, can anyone give me help on how/where to check the gearbox oil level?

 

[Boomyal]

Re: 165hp OMC I/O Gear box leak?

Could be the intermediate housing fluid mixing with water and pushing out thru the inside seal. Have you checked that fluid? What year is this unit?

 

[DukesFin]

Re: 165hp OMC I/O Gear box leak?

No idea where to check it... I should have my manual this weekend. The unit is a '73 or '74.

 

[Boomyal]

Re: 165hp OMC I/O Gear box leak?

Originally posted by DukesFin:<br /> No idea where to check it... I should have my manual this weekend. The unit is a '73 or '74.

There is a flat screw plug, about the size of a dime, at the top of the intermediate housing right outside the boot. You may need to stick a straw, with your finger on top of it, into the hole and pull out some fluid and dump it in a clear glass for inspection. There is no drain plug for those years. <br /><br />There is a seal behind the ball gear and a seal inside the intermediate housing to keep oil in and water out. If the outside seal is leaking it might be forcing emulsified oil out of the inside seal and down into your bilge.<br /><br />The only other place the 'oil' could be coming from is the engine.

 

[DukesFin]

Re: 165hp OMC I/O Gear box leak?

I've got a "plug/screw" on the lower unit - Port Side, one on the upper unit - Starbord Side and another one on the upper unit in the front leading edge right above the exhaust port. (Those are the ones I noticed at lunch today when I went and looked at it.

 

[Boomyal]

Re: 165hp OMC I/O Gear box leak?

Check this. If you do not have one of these plugs, then your drive shaft bearing is lubed by a zerk fitting instead of 90w oil. Not sure what year they made the change over. This pic is of a '75.<br /><br />If your unit is lubed by grease, I doubt that it would create 'creamy oil' in the bilge even if the seals were leaking.<br /><br />

 

[DukesFin]

Re: 165hp OMC I/O Gear box leak?

Pictures are worth a thousand words... and sometimes, dollars! Thanks. <br /><br />I'm pretty sure I don't have that plug though. I'll check again after work...<br /><br /> Thanks!

 

[Boomyal]

Re: 165hp OMC I/O Gear box leak?

If you don't have it then I suspect your unit is alot older than '73-'74. But come to think of it, even the units that used grease have some kind of a top plug. You needed to remove the plug to keep from blowing out the seals when you applied the grease gun.

 

[DukesFin]

Re: 165hp OMC I/O Gear box leak?

Okay - I do have the plug after all! I dipped a straw just a little bit down in there (couldn't get it down too far at all, maybe an inch or two), and pulled out some oil, marbled with the "creamy" sludge. Since I'm not seeing any leakage on the outside of the nuckle gear, I can assume that the "inner" seal is failing? If this is the case, I see three bolts on the outer housing above the exhaust port. Can the assembly be removed this way or am I going to have to remove the whole outdrive to replace the inner seal?

 

[Boomyal]

Re: 165hp OMC I/O Gear box leak?

Both seals are failing. The outer is letting water in and the inner is letting the emulsified oil out.<br /><br />Not real sure how you replace the inner seal. I know it does not appear to be accessable from the motor side. I guess that is where the manual will come in handy. Hopefully it can be replaced from outside (pulling outdrive & ballgear/drive shaft)<br /><br />The outer seal will come out with the drive shaft. Not even sure here if you need to press the bearings off the drive shaft, to replace the outer seal, or if the seal can be replaced when you pull the ball gear off the shaft.<br /><br />Needless, both need to be replaced and now is the time to git-er-done, before you damage the shaft and intermediate housing. <br /><br />You also want to inspect the splines on the driveshaft. The earlier electrics had a 25 spline shaft and coupler. They were very fine splines and subject to wear. I replaced both my shaft and coupler with the later 20 spline set up. They never wear out.

 

[DukesFin]

Re: 165hp OMC I/O Gear box leak?

Boomyal: I really appreciate the help. I'll have the manual later today, for sure. If you're ever getting around the Atlanta, GA way, let me know... I owe you one!<br /><br />I'll do a photo anthology of the work and post it.

 

[Boomyal]

Re: 165hp OMC I/O Gear box leak?

Dukes, was thru Atlanta three Thanksgivings ago, to visit my daughter at Bob Jones University in Greenville SC. It was a bit chilly so we drove down to Hilton Head looking for some heat. Seems it was abnormally cold there for that time of year. I really liked the South. I miss those Cracker Barrel breakfasts. May be a while before I get back that way but thanks.