Old Johnson 25 hp

I bought an old fishing boat, came with what I was told is an old 25 hp Johnson. The boat is a 1973, and I suspect the motor is around that vintage also. How can I tell what this motor really is? The thing runs great, but I think it has a problem with a seal in the lower unit. After pulling it out of the lake, it will drip gear lube from the lower end. The gear lube appears to be coming from above the fill hole. Yes, I am brand new at boating, so forgive me if I'm not getting my terms right. Is there any tricks to pulling the lower end off? Is there a schematic that I can get somewhere? Am I right that there is a seal in there? Any suggestions out there to help this new boater?

Thanks!!
signed "dummy"

Re: Old Johnson 25 hp

Are you sure it's gear lube? Most two cycles drip unburned fuel/oil mix out of the leg through the drain holes.

Re: Old Johnson 25 hp

what is the model # of the transom mount, usually under the front of the motor where it clamps to the transom.

Re: Old Johnson 25 hp

Did I mention earlier, that I was a newby dummy to this world? I believe you are correct, that the oil I mentioned was unburned 2-cycle oil. I also pulled the plug on the lower end to check the level and cleanliness of the gear lube. I had changed it yesterday. I was nice and clean, no sign of water, and appeared to be full.

The number on the transom is: 250030-e02373. Can you identify the motor by that?

There is a knob, about 1 1/4 inch in diameter on the front of the motor. This moves a rod that goes into the front of the motor. Is this an air mixture control, or something??

Thanks
Jim