Need some info for a 2.5 Johnson

[Dave Barnett]

My son and I recently received an old 2.5 Johnson outboard for free. We are trying our hand at restoring it. The motor is between a 1946 - 1950. Are these motors some of the older ones that used SAE 30 oil in the gas mix? It says on a website I found for this motor that it uses 5.5 ounces of oil to 1 gal for a 24:1 mix. They didn't specify what type oil to use. I had an old Clinton years ago that used SAE 30 oil in the gas mix. Age being comparable I was just wondering. The motor is an HD 25. One final note, we have one cylinder that is pretty gunked up. Could we use a cylinder hone to clean it up or should we take a different tack? Thanks for any info. God Bless. Dave

 

[psteurer]

Re: Need some info for a 2.5 Johnson

I would use the current 2 cycle oil. One could use SAE 30 oil back then because 2 cycle oil was not that easy to come by except in the big cities.

For the cylinders, when you say gunk do you just mean carbon deposits? You might be able to get by with soaking the cylinders for a few days with some oil or Sea Foam and removing the gunk that way.

 

[Dave Barnett]

Re: Need some info for a 2.5 Johnson

Yeah the "gunk" is carbon. It is caked to the inside of the cylinder. How much "scraping" can you get away with on a cylinder? Is scratching the cylinder walls a big no no? I think I'm going to buy new rings for it so I want to be sure not to goof something up that I can't fix. Thanks for all input. Dave