Johnson 4 HP - milky gearcase oil

[djmeaney]

I have a 2000 Johnson 4 hp with forward and neutral -- spin the motor for reverse. Mod # J4RLSSM (long-shaft).

Replaced the water pump (with kit) a few weeks ago before going out the first time. Figured I would change the oil in the gearcase at the same time -- no oil came out. Hmmm, I had changed oil last summer and figured that may be I had drained in the Fall and forgot.

Over the weekend, I ran it about for an hour in a test barrel -- ran great. Took out of barrel and left on back of boat. About 2 hours later I noticed milky oil draining the gearcase fill screw. I drained oil from gearcase -- there wasn't much left.

At this point, I'm figuring it must be a pretty good leak since it only ran an hour, most of it at idle.

Time to tear down gearcase and replace all seals? Is there a kit for such a thing -- couldn't find one?

Aside from a vacuum/pressure test, which I wasn't planning on doing -- we're talking about a real small motor here and I likely going to tear it down anyway -- is there anything else I should consider?

Thanks,

 

[Xcusme]

Re: Johnson 4 HP - milky gearcase oil

Well. there's one thing you can try BEFORE you rebuild the lower unit....try replacing the seal(s) on the fill the vent screws and running again for awhile.

 

[Big Jay]

Re: Johnson 4 HP - milky gearcase oil

I think there is supposed to be a plastic washer on the drain/vent screws to complete the seal on the gear-case...

Is it possible they are missing?

It'd be nice to not have to dig into the gear-case if you didn't have to

 

[hidef]

Re: Johnson 4 HP - milky gearcase oil

The 4 horse lower unit is pretty simple to work on. You have seals for the drive shaft (11) and the prop shaft (5) that could be leaking the other place you can have leaking is the bearing housing O-ring (2) and of course the little plastic washer on the drain and fill screws (16).

Johnson Gearcase Parts for 2000 4hp J4RLSSM Outboard Motor

 

[boobie]

Re: Johnson 4 HP - milky gearcase oil

Pressure test it and you'll know exactly where it's leaking. No guess work.

 

[nwcove]

Re: Johnson 4 HP - milky gearcase oil

I have a 2000 Johnson 4 hp with forward and neutral -- spin the motor for reverse. Mod # J4RLSSM (long-shaft).

Over the weekend, I ran it about for an hour in a test barrel -- ran great. Took out of barrel and left on back of boat. About 2 hours later I noticed milky oil draining the gearcase fill screw.

Thanks,

if its leaking from the fill plug......well you know.

 

[azhunter]

Re: Johnson 4 HP - milky gearcase oil

If it is leaking out through the fill hole, it's a pretty safe bet that it is also leaking in through the fill hole.

 

[djmeaney]

Re: Johnson 4 HP - milky gearcase oil

Thanks for the help. I happen to have an extra 'O' ring for the vent and plastic washer for the fill.

How would you pressure test the gearcase? with something like a bicycle pump?.

 

[boobie]

Re: Johnson 4 HP - milky gearcase oil

You can make a tester but it would probably be easier if you just took it to a dlr.

 

[djmeaney]

Re: Johnson 4 HP - milky gearcase oil

You guys were spot on the fill hole washer! I removed the screw and through the draining oil it took me a few minutes to realize the washer wasn't worn -- it was completely missing. Refilled the gearcase ran it for another 45 minutes and no leaking oil. Now I drain the gearcase again to as much watery oil out as I can -- refill again and be done with it.

Thanks

 

[Big Jay]

Re: Johnson 4 HP - milky gearcase oil

Excellent !

It's nice when it's that easy