ORIGINAL: loughbd
Is that why OS recommends the Type F plug and Enya recommends their #3 and everybody else makes a four cycle plug which is at the very high end of the heat range?? You need a hot plug to keeps things going during the exhaust stroke. Get a copy of C. Lee's books on the 4 cycle engine or any of the other engine gurus and look at what they say.
Those plugs are best with low nitro, 10% and lower. For high nitro that is 20% and greater the K&B 4C often works the best. No idleing problems either. If you like hot plugs try the Thunderbolt four cycle plug. IMO too hot for anything other than FAI fuel and inverted engines. But will make lots of smoke and burn lots of fuel. But power will be off.