I have a 2012 Honda BF200A just over 300 hours. Having problems with intermittent rpm surging- almost seems like starving for fuel and speeds up, but then slows back down. RPM's jump up to 300 - then it might run smooth for several minutes and then do it again. I have replaced plugs and the oxygen sensor which didn't solve the problem. I always run Non E premium fuel. No visible water in the motor mounted separator and the larger water separator is clean. This is most noticeable when running at upper rpm's. Any ideas?