dinghy outboard intermittent no start

[ajf10]

I tow a small dinghy behind my Catalina 27 sometimes. The engine is a 4 hp yamaha 4mshq, 1992 vintage, 2 stroke. It has an integral fuel tank and no fuel pump or primer bulb.

Whenever I start the engine in my driveway, it starts right up on the first pull. But after transporting it in the car on its side, or after towing the dinghy with the engine on it, it often won't start. After a while sitting it will often start later.

I am trying to figure out if this is a flooding issue, or if there is air getting into the fuel line between the tank and carb due to the bouncing of being towed behind the boat, or due to laying on its side in the car during transport.

I also wonder if it could be a bad fuel issue, although I filled the engine tank no less than a month ago and keep it sealed except when I open the breather valve to run the engine. The premixed oil is carefully measured, I also use a carefully measured ethanol treatment in the gas.