I accidentally put marine grease in the lower unit of my 1963 Johnson Seahorse....

[jbucking]

Okay, sorry for the long post, I already know it was a bone headed move, but the containers are almost identical. It was hot here in FL and while changing my lower drive fluid I accidently filled it most of the way up with a tube of marine grease. (Old 1963 Johnson Seahorse) I have researched this online and some say to clean it out with kersosene or diesel fuel and replace with the proper lube, but I have also found sites where people recommend using grease in their lowers and mention that many commercial fishermen use grease in their lower. Honestly, when I think about it.... what can hurt ? I did top it off with regular lower drive fluid. Grease is a petroleum product. If it were cold like up north then a lower viscosity fluid would make sense, but here in FL where it is hot, what could it hurt ? I think cleaning out could do more harm than good.

 

[robert graham]

I'd remove/flush it out and put the correct marine lower unit 80-90 gear lube.....

 

[harringtondav]

+1^ Run it on muffs, no load, as is, to mix the lube and grease so it will flow out easier. Then add heat with a heat gun or hair dryer to further thin it out. Drain what you can, and refill to the top with mineral spirits or kerosene and let it soak for a few days. Let it drain well then add lube. Lube is cheap, so I'd run it again on muffs to emulsify any remaining solvent and grease, drain, refill and go boating.

 

[Sea Rider]

Don't soak lower leg with kerosense could be darn harmfull for rubber oil seals. Remove both upper and lower drain plugs, place a container on lower leg, blow out the grease and gear oil mixture blowing a can of compressed air through upper plug.

Fill lower leg with 80-90 gear oil, let gear box work for some minutes while geared, empty contents. Fill with any good quality 80-90 multigrade gear box oil.

Won't need to go for the second step as the first one will probably remove all the gear box contents..

Happy Boating

 

[Grub54891]

Back in the day, newly married, kid on the way, I had old attwater Scott given to me. The lower leaked pretty bad. I put a couple pumps of grease in, then would top off with lower unit lube. I'd do this on every outing Never wrecked what was left of the gears in 5 years.

 

[jbucking]

Thank you everyone's response. I just keep wondering... what can it hurt ? There are no pumps down there that require the fluid to be pumped, just gears. I will likely remove it, but I can't think of why it would do any damage.

 

[racerone]

But bearings on these older motors were designed to run with oil !-----These bearings were designed by experienced folks who know how oil and bearings work.---What is the model # of the 63 Johnson ?---There is a difference between a 3 HP and 75 HP electric shift motor !------Grease does not flow / build up the hydrodynamic wedge like oil does.-----Confused yet ?

 

[harringtondav]

+1^ on everything. I'm a retired drive train/trans engineer. Grease has it's place. You can find it where the mfg provided a zerk. A high speed, highly loaded gear box, especially spiral bevel gears requires liquid lube.

 

[Sea Rider]

Yep, personally wouldn't risk greasing a gear box intended to be filled with proper gear box oil. Don't think that grease will hold well on gears working at high rpm for long time periods. Gear box internal parts could turn costly if severely screwed by such practice. Use grease where required, oil when mandatory..

Happy Boating

 

[gm280]

Not to challenge anyone's ideas or opinions, but I have a few die grinders (Dotco, IR etc) that I use near daily. And while oil is recommended in the air inlets for daily use, there is also a fitting in the gear assemblies that you insert grease into those gears. They are helical cut gears that spin at very high RPMs reaching 20,000 RPMs or more. And that section takes grease, not oil. So while I too would remove the grease and use what is supposed to go in there, grease does work in very high RPMs in such situations. JMHO

 

[Chris1956]

Those Johnny gearcases have brass bushings between the steel gears and SS propshaft. They are a "no play" fit between the gears and shaft. Do you really think heavy grease will get on those bushings and lubricate them?

 

[racerone]

Has the original poster updated with a model # of the Seahorse ??

 

[jbucking]

It is a Seahorse model CD20R, serial number 2390522. I believe it is a 1963 model. Thank you for everyone's input. all points, well made ! I will wait for a good hot day to start flushing out the grease.

 

[racerone]

A 5.5 HP model.-------A wonderful smooth running motor.------What maintenance has been done ?---Replaced water pump impeller ?----Inspected shock absorber in lower unit ?

 

[JimS123]

Several of the antiques in my collection actually call for grease in the lower unit. The newest one is a 1955 Mercury 10 HP direct drive. Guess they were built different back then.

That particular Merc was my daily driver way back when. Never changed the grease, just put a few squirts in every Fall.

Just sayin'...

 

[racerone]

Perhaps the old Mercury had ball bearings instead of plain sleeve bearings.-----Ball bearings are perhaps not a " better design " in my opinion.

 

[JimS123]

Perhaps the old Mercury had ball bearings instead of plain sleeve bearings.-----Ball bearings are perhaps not a " better design " in my opinion.

I am of the opinion that everything today is of a better design. Technology is the key word.

However, in the case of my old prized Merc, as a kid I used 10w30 because it was cheaper than OB Motor Oil, never changed any parts except when the pawls broke on the recoil starter. I said "any parts". I DO know better today, though, and today's Daily Drivers get better maintenance.

I only run the old girl on special occasions,a and always thinking of Grandpa, since he gave her to me. After 64 years she's still pumpin' water with the original impeller.

Maybe it shouldn't be "better design" for this thread, but rather "They don't build em like they used to"....

 

[racerone]

So did the old Mercury have stainless shafts like some other motors in 1955 ??

 

[DeepCMark58A]

There is a guy in Hayward WI that has a very solid reputation as a Mercury expert. I have sent 2 lower units to him for a complete rebuild. He fills the lower with grease, I will take his word on it.

 

[82rude]

My 1939 22.5 hp speeditwin takes grease also.I had a 64 /65hp merc that leaked and couldn't seal it up for the life of me so in went grease and she lasted for years.JimS123 did the merc have a metal impeller like my 39 speeditwin?