Kayaker, higher octane fuel will not help cold starts. it will start better with the lowest octane the engine will tolerate (not detonate). the difference is small but octane raises the autoignition temperature of the fuel. auto ignition temp is the temp that will ignite/ start the burn of the fuel. the reason starting fluid works is because it has a lower autoignition temp than gasoline or diesel. diesel starts from the heat of compression because the auto ingition temp of diesel is lower than gasoline. gasoline needs the heat of the spark to ignite the fuel. I also would not be afraid of a small amount of starter fluid. the problem with starting fluid is it lowers the autoignition temp and can result in detonation which is not good for the engine. but, it starts the burn/combustion process at a much lower temp. as I mentioned earlier, higher voltage at the coil when towing can increase the voltage of the spark at the spark plug. higher voltage means higher temp which increases the chance that the gasoline will ignite. another option is park it on a hill and push ride it downhill in a gear that will spin the engine.