Approximate cost for lower unit seal replacement

[metriccrescentwrench]

1990 Johnson 200. I'm seeing gear lube dribbling down the skeg, so there's gotta' be a bad seal. I'd normally do the work myself but don't really have time right now, so I'm wondering what a dealer might charge for replacing the seals in the lower unit.

I bought this engine in November for a boat I'm restoring, and haven't even had a chance to take it out yet. It was on the guy's boat I bought it from when I picked it up, so I was able to see it run and check it over, didn't see any oil leakage then. Since then it's been laying on my trailer and I just hung it on the boat last week.

 

[blimp]

Re: Approximate cost for lower unit seal replacement

are you 100% sure it is gear lube? These motors usually have some unburnt gas in the exhaust and leg which can escape through the exhaust in the prop/lower unit. If you just tilted it upright after sitting on a trailer for a while it likely is just draining some of this buildup gunk.

You should change out the lower unit oil regardless, check it for gray or milky color. This indicates a water intrusion. If it is black, you are good to go.

good luck.

 

[metriccrescentwrench]

Re: Approximate cost for lower unit seal replacement

Yes, it's gear lube, not exhaust "gunk".

 

[AEROCOOK]

Re: Approximate cost for lower unit seal replacement

Clean it well with degreaser and see if you can find the specific source of the leak... Could be as simple as a missing / bad gasket on the fill / drain plug.

 

[metriccrescentwrench]

Re: Approximate cost for lower unit seal replacement

It's not coming from either plug, wish I could get off that cheaply. It was coming out from around the front of the prop, and when I pulled the prop it doesn't appear that it's the rear seal, so I see no way around the fact that the lower unit needs to be pulled.

I'm still working on getting this boat rebuilt, otherwise I'd just tackle it myself. Right now I'm so tied up with working on the boat that (so long as it's not real expensive) it's worth it for me just to let a mechanic deal with it. That's why I'm trying to find out what others have paid for this job, so if I get quoted something double that I can tell them to take a hike.

 

[blimp]

Re: Approximate cost for lower unit seal replacement

If it is coming out the front of the prop, i'm still betting it is just unburnt gas/2stroke oil mix...which is perfectly normal for these motors.

 

[blimp]

Re: Approximate cost for lower unit seal replacement

does it look anything like the oil in the pictures in this thread?

http://forums.iboats.com/showthread.php?t=398257&highlight=lower+unit+leak

 

[metriccrescentwrench]

Re: Approximate cost for lower unit seal replacement

I'm very, very, very certain it's gear lube. I know what it feels like and I know what it smells like. And this is very clean gear lube that's leaking, there's no mistaking this for unburnt fuel.

 

[wilde1j]

Re: Approximate cost for lower unit seal replacement

Prop shaft seals (there are two back-to-back) replacement may be possible w/o dis-assembly of the LU ... if so, fix should be less than $100 - $125. Note I said "may", since not all LU's may be done this way and the shop manual usually describes the repair as needing the bearing carrier pulled. If the LU needs to have bearing carrier pulled, it's a lot more ... say ~ $250 - $300 or so, depending on shop labor rates where you are.

To replace other seals (shift rod and drive shaft), the LU needs to be dropped and the water pump pulled, so it's more again.

 

[metriccrescentwrench]

Re: Approximate cost for lower unit seal replacement

Thanks, that's good information.

I had a chance to drain the lower unit last night and the oil was very milky, as expected.

When I tilted the motor up a small amount of milky oil came out of a weep hole above the AV plate, so it's looking like either the drive shaft seal or shift rod seal. But if that's the case I'm wondering how oil got down to where it was leaking out around the front of the prop.

 

[wilde1j]

Re: Approximate cost for lower unit seal replacement

The LU needs to be pressure/vacuum tested to be sure where the leak is.

General procedure:
1) drain gear oil
2) pressurize to 15 psig max
3) good LU will hold some pressure/vac for 45 minutes
4) submerge in water to find leak(s)

If there's any shaft grooving, make sure to offset new seal seating away from grooving.

 

[ezeke]

Re: Approximate cost for lower unit seal replacement

To find the leak, drain the gearcase and use either the vent or drain hole to apply air pressure to around 12 PSI. If you don't hear the air leaking, drop the unit in the water so you can see the the air bubbles.

Well equiped service shops should have the puller to remove the prop shaft seals without removing the bearing carrier.

Complete seal kits are the least expensive way to go if you want to do the job yourself.