I've been running a NGK BP6ES spark plug in my Predator 6.5 engine at my altitudes of 6,000-10,000 feet. The engine runs very strong and I have not changed out the jet for high altitude. The plugs insulator looks a little dark but not fouled.
Would there be any advantage going to a hotter plug such as BP5ES? I am not sure changing the jet out would help, and I would be more concerned running the engine too lean and possibly doing damage to the upper end?
Would there be any advantage going to a hotter plug such as BP5ES? I am not sure changing the jet out would help, and I would be more concerned running the engine too lean and possibly doing damage to the upper end?