BTW: on my ryob's im getting about 7500rpm on an APC 18x8 wide blade using the conversion parts and carb from www.wackerengines.com . If you can turn your own flywheel down about $50 will get all the parts INCLUDING the large bore carb from him. Spend a little extra and get his muffler too. Hands down the best one out there and not because its the cheapest. The pipes are removable so you can make two holes in a cowl to put them through instead of a huge gash to slide the cowl around them