Lower Unit Nightmare! Please Help

[smokeyblaze]

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[gss036]

Re: Lower Unit Nightmare! Please Help

Definately has water intrusion. Buy a couple sets of seals and at least a quart of lower end grease, fill it up and run for about and hour and then drain again. If you keep getting water, find somebody to do a pressure check for prop and shaft sealsand replace if needed. Not a real expensive fix but needs to be done.
Did you find any metal shavings? If not you should be ok.

 

[smokeyblaze]

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[gss036]

Re: Lower Unit Nightmare! Please Help

Just fill the lower end with the 85-90wt grease and run it since you did find any metal. There are seals for the prop shaft and one fron the main shaft from the motor. The lower unit will need to be removed to test them both to determine were the water is getting in.
FIRST THINGS FIRST, do as I said above and then take it from there, you may just have had leaking gaskets from the drain and fill screws. Yes, you need both. They use the same size and a buck apiece, that is cheap.

 

[Droll]

Re: Lower Unit Nightmare! Please Help

What kind of seals do I need? Do I fill it with gear oil and lower end grease when I run it or just grease?
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Easiest option would be to get the whole lower unit seal kit #26-55682A1
Or just :

• #26-76868 prop shaft seals, need 2
• #12-45176 washer under fill/vent screw , need 2
• #25-29976 O-RING bearing carrier
• #26-94038 drive shaft seal
• #26-16977 drive shaft seal
• #25-33145 O-RING lower water pump housing

As for lubrication... you should fill the lower unit with gear oil designed for use on outboards...

Arne Kjetil

 

[Don S]

Re: Lower Unit Nightmare! Please Help

What you need to do is pull the lower unit, drain it completely, and do a pressure and vacuum check on the lower unit to see exactly where it's leaking. With the pressure test, and a spay bottle of soapy water it will be very easy to see where the leak is.
You will NEVER go wrong with using Mercury Hi Perfomance gear lube. You wouldn't have that seperation of water and oil, which can cause rust on gears and bearings.

 

[Silvertip]

Re: Lower Unit Nightmare! Please Help

And please everyone, stop calling lower lube "grease". It is not grease. It is actually gear oil but commonly called lower unit lube. It is available at any discount store (such as WalMart) that sells boating supplies. While you are there, buy the pump that screws into the bottle so you can pump the lube into the lower unit.

 

[smokeyblaze]

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[Chris1956]

Re: Lower Unit Nightmare! Please Help

Dip your finger into the milky gunk and smell it. If it stinks, it is gear lube. if it smells like gas, it is likely residual 2 cycle oil.

if you still have water intrusion, you will need to replace some or all of the gearcase seals. The driveshaft and waterpump base seal are pretty easy to replace, and have always been the problem on my '77 Merc 1500 inline six. Hopefully you will have the same kind of luck, since the propshaft seals are pretty hard to replace without some special tools.

 

[smokeyblaze]

Re: Lower Unit Nightmare! Please Help

Its gear lube , Is this normal?

 

[Chris1956]

Re: Lower Unit Nightmare! Please Help

Gearlube means that the prop seals are likely leaking. You might start looking around for a used LU. it may be cheaper than having the repair done. Check under the prop for some fishing line. Fishing line tears up the seals pretty good.

 

[smokeyblaze]

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[smokeyblaze]

Re: Lower Unit Nightmare! Please Help

What kind of damages could this cause?

 

[gss036]

Re: Lower Unit Nightmare! Please Help

If you run it dry, it will just grind up the gears and seize and then you have no choice but replacing the entire unit. Might be cheaper to find a used lower unit that is not leaking, but then again, you might get one that is also bad. Best to get it fixed instead of putting it off as it will only get worse.

 

[halmc]

Re: Lower Unit Nightmare! Please Help

You ain't got a nightmare, dude, you got a nasty little bad dream at the worst.

Replacing the seals in that unit is duck soup if you have:

1) a SELOC manual appropriate to your engine-- not Haynes, not Chilton, but the real deal: SEOLC. I have turned wrenches for years and would not attempt outboard repairs w/o the manual, avialble from the nice folks who make this forum available.

2) rudimentary mechanical skills and tools.

3) some beer.

Really, if you've got basic skills, and the manual you can do it. You definitely have water intrusion, most likely from the propeller shaft seal. If not there, then the larg O ring that seals your bearing carrier, or perhaps at the water pump. The Sierra water pump kit includes all the seals you need for the top, and the two other items (prop shaft seal and O ring) are both available from iBoats; and the bearing carrier retaining nut (if your engine is so equipped) from your local merc dealer.

You will most likely need to remove the bearing carrier. If yes, I found the special tools I needed at Home Depot. PM me for details.

Lastly, replacing the lower unit because of water intrusion is like trading in your car because the horn won't blow. OK, maybe because it needs a new A/C evaporator, but YOU CAN (most likely) DO IT!!!

 

[Starppy]

Re: Lower Unit Nightmare! Please Help

First, lets be very clear. It is not grease in those units, it is gear OIL. Don't confuse the two because some older Mercs like the 75a and 78a dock busters with direct reverse actually used GREASE instead of gear oil.

Yes, your problem is the seal. Sounds like a prop shaft seal, but it probably would not hurt to do them all. You can actually order a kit with all the seals for the lsoer unit. You can do it yourself, but it does require special tool taht can be quite pricey. No offense, but I doubt you could get the real thing at Home Depot. Definately skip the beer while doing this job. The carrier retaining nut is a real bear to get off even with the right tool and there are other hazards to consider.

As much as I hate taking an older outboard to a dealer (their all lying SOBs) this is one case where it may make sense. i had a complete seal kit and pump put in the lower unit of my 1972 650 last year and it only cost $275. Well worth it in my book since this is a repair that only needs to be done once or twice in an outboards life.

Replacing the whole LU is pretty damned silly. A better analogy than halmc's is replacing a car's entire drivetrain because the u-joint went out.

 

[sportsmanphil]

Re: Lower Unit Nightmare! Please Help

I didnt see this mentioned but use proper marine grade gear oil, as automotive gear oil's expansion rate is different and could blow out your seals once it gets warm.

Also, in your photos, there wasnt much oil period. If I am not mistaking, you have to put your throttle in the forward position to drain the all the gear oil out of the foot.

Replacing the seals isnt hard at all. A gear puller with reversable arms can be used to pull the hub. You can pick up one of those about anywhere.

Any chance you had some water freeze in the foot this past winter? Not sure where you are from (I didnt look before I started this reply )

 

[Karl_Childers]

Re: Lower Unit Nightmare! Please Help

Replacing the seals in that unit is duck soup if you have:

1) a SELOC manual appropriate to your engine-- not Haynes, not Chilton, but the real deal: SEOLC. I have turned wrenches for years and would not attempt outboard repairs w/o the manual, avialble from the nice folks who make this forum available.

2) rudimentary mechanical skills and tools.

3) some beer.


I'll agree with all the above.....If you can get the thing apart. If it's spent its life in salt water, pack a lunch, or open your wallet.

Rob