r u using the actual roto start? or a cordless drill? u could be spinning the crank the wrong way these motors r pretty simple it may just be to rich to start try leaning the hsn a bit at a time. when u pull the glo plug out u should be able to tell if its flodded if so just pinch the fuel line and crank it abit to flush out the fuel another way to tell if its to rich is after trying to start it with no luck remove the fuel line from the motor and try to start it give it a sec and if it starts eventually with no fuel feed you know its to rich

Hope this helps
Dustin