Suitable Lower Unit Oil for 1971 Johnson 6 HP

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RM58

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I just acquired a 6 HP 1971 Johnson outboard. What would be a suitable lower unit oil to use in it? Also, what is the proper fuel/oil ratio for this motor. I think it is 50 to 1 but I want to make sure.

Thanks
 
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Daviet

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Re: Suitable Lower Unit Oil for 1971 Johnson 6 HP

80/90 wt lower unit oil, most auto parts stores carry it, make sure it is a marine grade lower unit oil.
You are correct, 50:1 is the proper mixture.
 

phillnjack2

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Re: Suitable Lower Unit Oil for 1971 Johnson 6 HP

it don't need to be anything special like marine grade at all.
if the seals are in good shape then any of the ep 90 oils will be fine.
no water or moisture gets in the gearbox on a outboard engine.
its not like a car back axle that has a breather pipe !!!!! its a complete sealed unit.

as above 50 to 1 is perfect.

.
 

RM58

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Re: Suitable Lower Unit Oil for 1971 Johnson 6 HP

Thanks for the replies.
 

Vic.S

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Re: Suitable Lower Unit Oil for 1971 Johnson 6 HP

it don't need to be anything special like marine grade at all.
if the seals are in good shape then any of the ep 90 oils will be fine.
no water or moisture gets in the gearbox on a outboard engine.
its not like a car back axle that has a breather pipe !!!!! its a complete sealed unit.

as above 50 to 1 is perfect.

.

But seals can and do leak then water gets into the lower unit.

Outboard engine gear oil contains emulsifiers and corrosion inhibitors to guard against the effects of water intrusion.

You may use an automotive oil, I may do also, but the sound advice to give others is to use an outboard gear oil for the above reasons. Its up to them whether or not to follow the advice.
 

phillnjack2

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Re: Suitable Lower Unit Oil for 1971 Johnson 6 HP

I think someone needs to go look up the ingredients of the oils, auto v marine. its the same stuff.
you might get a shock as to whats in them under the fancy labels.
oil spec sheets are easy to obtain !!!

I have used normal hypoid ep 90 in a outboard gearbox for years and never ever had a problem with it.
regular checks for the oil are needed anyway, so it is not like on a car where nobody ever even bothers to check it.
I change gear oil on a 2 yearly basis unless I have done a lot of hours.


if you actually look in a proper service manual for outboard engines it will specify what oils to use, this will give names of brands and the specs of the oil for instance sae 75w or hypoid ep 90 etc etc , now all oil companies that use the sae marking have the oil at the same viscosity and the same specification. that is why they have the specs !!!

mercury recommend mercury oil, but they don't actually make any oil, omc recommended their oil, yet again no omc oil refinery. the list goes on.
so where does the oil really come from ? and what exactly is it. only the spec sheet will tell you whats in it.

what do you think everyone used in the 1940's and 1950's ?

anyway that's what I do and wont be fooled into buying everything just because it says marine.



phill
 

Vic.S

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Re: Suitable Lower Unit Oil for 1971 Johnson 6 HP

I think someone needs to go look up the ingredients of the oils, auto v marine. its the same stuff.
you might get a shock as to whats in them under the fancy labels.
oil spec sheets are easy to obtain !!!

I have used normal hypoid ep 90 in a outboard gearbox for years and never ever had a problem with it.
regular checks for the oil are needed anyway, so it is not like on a car where nobody ever even bothers to check it.
I change gear oil on a 2 yearly basis unless I have done a lot of hours.


if you actually look in a proper service manual for outboard engines it will specify what oils to use, this will give names of brands and the specs of the oil for instance sae 75w or hypoid ep 90 etc etc , now all oil companies that use the sae marking have the oil at the same viscosity and the same specification. that is why they have the specs !!!

mercury recommend mercury oil, but they don't actually make any oil, omc recommended their oil, yet again no omc oil refinery. the list goes on.
so where does the oil really come from ? and what exactly is it. only the spec sheet will tell you whats in it.

what do you think everyone used in the 1940's and 1950's ?

anyway that's what I do and wont be fooled into buying everything just because it says marine.



phill

Yep both are GL5 spec but as I said outboard gear oils have additional emulsifiers and inhibitors ... or so they tell us... but perhaps you are accusing the manufacturers and distributors of deceit.

What happened in the 1940s and 50s is not relevant. Science, technology and engineering have moved on.

The fact remains people asking for advice on a forum like the iBoats forums deserve the best and correct advice not some cheapskate alternative. It's then up to them whether to follow it or risk their kit by saving a few halfpennies on a fill of oil.
 
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phillnjack2

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Re: Suitable Lower Unit Oil for 1971 Johnson 6 HP

british seagulls have used sae 140 for around 75 years, the newer models from 1978 use ordinary ep90 for gear oil.
these are about the most abused yet long lasting engines in the world of boating.
I have never come across one with worn out gears that had a drop of oil in them.

nuff said


phill
 

KyPoorBoy

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That's true. Water just mixes with my Seagull and I just check and change it once a year or every 20 hours of use , whichever comes first. Water never hurt it and.it takes the old 140ep
 

Vic.S

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That's true. Water just mixes with my Seagull and I just check and change it once a year or every 20 hours of use , whichever comes first. Water never hurt it and.it takes the old 140ep
Seagulls have bronze gears. They happily run in a mix of oil and seawater. The steel gears in modern outboards will not take kindly to that.

The later seagulls that use EP 90 have seals in the gearboxes . The older ones do not have proper seals. If you put EP 90 in an old one it leaks out too quickly.

Every year I just drain out the "milk shake" from the Seagull and refill with SAE 140 gear oil.

If I find any signs of water in my Evinrude I tear it down and fit new seals.
 
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