RE: 1/2A Size Boat Club
A better prop selection is what is really needed for these. Everything is so touchy because there's basically no horsepower to work with, and being able to vary the prop is the only link to get to what horsepower is there. Small changes have a big effect you can see on these.
My first boat I flip-started with my finger. Not impossible to do but be sure to bring a dry rag with you. Any water or oil on your finger or flywheel, it's going to get frustrating. Cracking the glow head open a little helps if you're not having any luck.
It is very important you have a good engine mount system, not just wood screws through the motor, or if you do...make sure theres lots of solid wood and use the longest ones you can find.
Most all of Dumas 1/2A boats are designed around 18" in length. Miss Thriftway, Atlas Van Lines, SkeVee-10, Short Stuff and SK-Daddle Jr. are all 18" long. I do not know if this is a good manufacturing length for them or if it just is a good size for the engine but I think it is about right.