Just had my powerhead repaired (#3 cylinder blown after only 68 hours) and the technician mentioned that the cylinder and piston were covered with carbon build-up. Powerhead never had anything but ethanol-free 91 octane fuel and Ring Free added every tankful and never run low on oil. Never ran it over 5500 RPMs. Anyone have any idea what might be causing the carbon build-up?
BTW, Jasper refused to make good on their powerhead that had only been run for 7 months and had just 68 hours on it. I'm not at all happy about spending $7k on that and getting hung out to dry by Jasper!!