Carborator and Lower Unit questions

bhughes

Seaman
Joined
Apr 28, 2009
Messages
57
Hello,

After having 2 lower units go bad on my 1958 18hp johnson (gears slipping), I finally upgraded to a 1974 25hp that I found for $300. It's not pretty, but it cranks and runs smooth which is all I can hope for.

I have 2 questions:
1. The guy I bought it from didn't have much knowledge about the motor as he had only gotten it from a guy and not yet used it. When we tried to crank it before I bought it, I noticed there was a screw or something missing from the bottom front part of the carborator and the gas was just spilling out of the hole when we tried to crank it. So, we plugged the hole with a nut that we found would fit in the hole and it cranked right up.
I think maybe there used to be some sort of adjustment needle there similar to the one right above there. Does anyone know what is supposed to be there and whether it's okay as long as it's running?

2. I also wanted to know how important it is to change lower unit oil. With these older motors, I feel like if I unscrew the screws to change the oil, there is a good chance that they won't be sealed as good once I change the oil because they are so old. So, is it better to have a leak and just change the oil more frequently, or just leave the oil that's in it since I don't see anything leaking out?
 

bhughes

Seaman
Joined
Apr 28, 2009
Messages
57
Re: Carborator and Lower Unit questions

Hey guys, does anyone have any suggestions about my questions? Thanks!
 

denL

Petty Officer 3rd Class
Joined
Nov 22, 2007
Messages
78
Re: Carborator and Lower Unit questions

I have a 1975 25hp Evinrude. I think that screw is used to release the fuel from the bowl. I would change the oil and buy new gaskets. Mine was missing the gaskets when I bought it and water was getting in to the lower unit. Once I changed the gaskets, no more water in lower unit.
 
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