Hi Tom, thanks, it been a lot of time and effort to get to this point. Because of where the carb is, i machined a solid brass flywheel, about an inch in dia, by half inch long, that slips over the crank, then a threaded piece of hex screws onto the crank. The hex has a 1/8 hole for the flex, held by a grub screw. Engine was pull start, remove pull start assy, machined up an aluminium pulley and mounted to the pto. Great fun, good luck, and I look forward to seeing you baby firefighter, cheers, Sam.