Yes it is a model 300. They were made 2 years actually, the 1935 3.7hp, and the 1936 3.7hp. Essentially the same motor I believe though, someone correct me if im wrong. They use a Champion J8C plug, gapped to 030. The point gap is 030 as well. Fuel mix 1/2 pint per gallon.
The other is obviously a Martin. George W Martin was the inspiration for these little black, great idling machines. He was a former outboard racer, and it was in the 30s that he began envisioning an outboard with mechanically controlled intake poppet valves. This ensure equal fuel distribution and uninterrupted acceleration. He got himself a patent, then went to the National Pressure Cooker company in Wisconsin to finance and produce his vision. So in '43a deal was struck where he would get a royalty for every motor sold. This lasted until the 60s until the National Pressure Cooker company finally sold off the remaining parts.
I have a few of them, they are really pretty good running motors. I run Champion J6Cs in mine, gapped to 035. Plug gap is 020. I run the same mix, 1/2 pint per gallon.
