71 Johnson 50hp milky lower unit oil

Right off the bat I'm new to the boat world, this is my first boat but i've been around motors my whole life but not boat ones. So I recently changed the lower unit oil and the water pump, the oil that came out was like a carmel color and just looked old. From my knowledge on a normal motor i know that is NOT ok but the boat, from what i was told was not on the water for 7 years from the previous owner which was last year. How can i tell if maybe a seal is bad? Is this really bad? and is it ok to put out on the water? I just replaced the water pump and the seals. I haven't put the boat out in the water yet because i replaced the floor and had to do a lot of TLC but im coming to an end and would love to put her out on the water to enjoy it. Thank you for any help!

Re: 71 Johnson 50hp milky lower unit oil

Quick way to tell if you have a leak is to do a pressure test on the lower. drain the LU oil, get a pump with a fitting that will fit the oil fill hole, put the LU in a bucket of water and pump air into the LU (very little pressure, I think its like 5 PSI max or you will blow out a seal). If you see air leaking out, then you have a leak. Since you have to tear down the lower anyway, you might as well fix all the seals.

Is your unit an electric shift? If so, remember that uses a special type of gearcase oil (referred to as Type "C"). The shifting system depends on this type of oil to work correctly, so be sure you are putting the right stuff back in.

Good luck.

Rgds

Re: 71 Johnson 50hp milky lower unit oil

Well I went to the local boat store and they gave me all the stuff i would need. I have already changed the LU oil and the water pump so it's done but is it ok to put the boat back out in the water?

eavega said:

Quick way to tell if you have a leak is to do a pressure test on the lower. drain the LU oil, get a pump with a fitting that will fit the oil fill hole, put the LU in a bucket of water and pump air into the LU (very little pressure, I think its like 5 PSI max or you will blow out a seal). If you see air leaking out, then you have a leak. Since you have to tear down the lower anyway, you might as well fix all the seals.

Is your unit an electric shift? If so, remember that uses a special type of gearcase oil (referred to as Type "C"). The shifting system depends on this type of oil to work correctly, so be sure you are putting the right stuff back in.

Good luck.

Rgds

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Re: 71 Johnson 50hp milky lower unit oil

It will run with a leaky lower unit, but consider if you are getting water intrusion in your lower, it can cause damage to your gears over time. Whats more, I don't know where you live, but if you leave that water in the lower and it freezes over the winter, it can split your gearcase.