I have a 18 hp IC oposed twin engine that starts and runs great, but after about ten minutes it wants to bog down like it is flooding. If I shut it off and let it sit awhile it does good for about ten minuets. What can be the problem?
Could be either a fuel or spark problem. You don't give us much info to help you. Have you checked for spark on both cylinders? Does it blow smoke, what color? When was the last time you had the unit completely serviced and checked over?