lower unit work before saltwater?

[chipacarbra]

Hello All, 1971 Johnson 6hp 2stroke. The original lower unit oil was milky looking, so I changed it and replaced both shaft seals, and oring and spaghetti-like seal around bottom casing. I ran it for about 15 minutes in a tank, and then dumped the gear oil again. It went from dark honey translucent when new, to old looking honey that is opaque in color. The only seal I can see that I didn't change was the prop shaft seal, but it looks real tight. I was using the basic gear oil from Wal-Mart. My question is, am I still getting water in the case? I want to put it in salt water next week, should I wait? <br />Any help will be greatly appreciated. I ordered a manual last week and still waiting on it.<br />Chip

 

[ob]

Re: lower unit work before saltwater?

Water in the gearcase will range from a milky color to simply just settling out clear in the bottom of the gearcase,depending on the mixing time and the emullsification properties of the gear oil used.Make sure that you used the Wal-Mart outboard motor gearcaswe lube instead of just auto gearcase lube.By your description,it sounds like perhaps your initial gear oil change is just flushing out some old dark deposits from the inside of the gearcase.

 

[alcan]

Re: lower unit work before saltwater?

Hi Chip<br />When resealing a l/u it is always best to replace all the seals. Next to worn drain plug gaskets the shift shaft seal and the prop shaft seals are probably neck and neck as best places for failure. When you complete a reseal job it is allways prudent to test it before use (bench test) To do this you need a vacuume pump/w gauge and a presure pump/w gauge. These tools can be obtained at any good auto supply or tool supply. I would suggest you follow the test procedures as outlined in any good outboard manual.

 

[chipacarbra]

Re: lower unit work before saltwater?

Thanks for the input, I will replace the three screw (drain & vent, and shift lever pin screw) gaskets/orings, and I will attempt to replace the prop seal also. I'm going to Napa to get correct gear oil, so I'll ask about the pressure tester. If I'm still getting a little water, how bad will this tear up the L/U in salt water?

 

[alcan]

Re: lower unit work before saltwater?

Salt water or fresh it really doesn,t matter. What matters is that oil and water don't mix. So where you have water you don't have oil. your gear case needs oil to properly lube it by keeping it cool. If you have a gear case full of water it just heats up and boils dry and seizes. So this is a little hard on gear cases, it is also hard on the power head. An old bicycle works fine for the presure test.

 

[rolmops]

Re: lower unit work before saltwater?

Alcan, when using a bicycle for a pressure test,do you go forward or backward?

 

[alcan]

Re: lower unit work before saltwater?

Thanks Rollmops, apparently I don,t know which way to go. I should have written bicycle tire pump.

 

[rolmops]

Re: lower unit work before saltwater?

Sorry,sometimes I just can't stop myself

 

[chipacarbra]

Re: lower unit work before saltwater?

Thanks Alcan, and rolmops, I almost made a mess of my ten speed. I just finished replacing the rest of the seals, I think. I replaced shift shaft oring, drive shaft bearing, prop shaft oring and bearing, spaghetti looking seal for bottom case, oring on shift pin screw, and plastic washers on both drain plug and vent plug. I kept thinking I had one left over oring, a skinny, kinda large (1 1/2" or so), but now I don't remember. I live in the desert, New Mexico, so the Auto Parts stores don't have much of a Marine section- the only gear oil I could find was something in an oversized toothpaste shape squeeze tube called high performance/ultra pressure gear oil for outboards. Will this work in the l/u? I appreciate all your help, I'm on my way to Kino Bay Mexico, and if I get this together, vacation never woulda tasted so good!<br />Chip

 

[alcan]

Re: lower unit work before saltwater?

Any 80/90wt gear oil will be fine in this case.