Re: Milky colored lower unit oil?????

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Posted by Ed Mc. ( on July 02, 2005 at 22:20:13:

In Reply to: Milky colored lower unit oil????? posted by Mo Khan on July 02, 2005 at 18:43:14:

The most likely cause of rapid loss of gear oil is a bad driveshaft seal. This oil seal is right under the water pump plate, which is the 'suction' side of the water pump.

This 'suction' pulls the gear oil right thru the leaking seal. Water displaces the oil until it's all gone.

Your gears and bearings will wear excessively unless you remedy the cause of leakage.

You'll need to remove the lower unit, then the screws holding the water pump housing, impeller, pump plate in place. The seal should be visible at this time. You'd pull the seal out and drive a new one in.

I expect you should have a manual shift motor, which will have an oval window in the side of the mid-section of the motor (the exhaust tower or 'leg'). Inside this window is the coupler for the shift shaft; you undo the lower screw and after removing the bolts which hold the lower unit to the center section, the lower unit will come off.

Be sure to renew the driveshaft O-ring at the crankshaft splines, when you're reinstalling the lower unit put a dab of waterproof grease on the driveshaft splines but not on the top. Rotate the flywheel clockwise (remove the spark plugs!) when inserting the lower unit to help engage the shaft.

Put a thin coating of waterproof boat bearing grease on all bolts; I use Sta-Lube blue grease, Good Stuff.

It will probably help to get a manual if you plan on doing the work yourself. Or copy the info out of manuals at your local library.

A couple of pointers: check the area of the driveshaft where the oil seal rides upon. If the shaft is badly worn there, it'll still leak even with a new seal.

A few ways to fix: pull the shaft out and take it to a machinist to weld repair the damaged area and straighten the shaft; drive a Speedi-Sleeve or Redi-Sleeve stainless repair sleeve over the damaged area; or use a different-style seal which hits the shaft in another spot. I've found that the driveshaft oil seal out of an older 35, 50, or 55 HP Chrysler (or Force engine too I imagine) works perfectly on these lower units. This seal has (2) lips instead of (1) so it'll seal better in any case, and was a lot cheaper than the standard OMC oil seal.

If you get in a jam, do a little research at the site, theres a very active Johns/Ev forum and lots of D-I-Y repair tip articles.

You can get by, by changing the oil every time you take it out but eventually you'll need to fix it. Do not run this motor in salt water unless you fix the leak, the salt will tear up the gears and bearings regardless of how often you change the oil.

HTH and G'luck.........ed

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