Re: new sparkplug
It's best to stay with Champions on that motor. Especially if you're using something other than the recommended (fresh) 87 octane. The motor was designed to run Champions and other brands tend to have different burn properties. If it were mine I'd use the QL77JC4's. Since you didn't say how the motor is being used we'll assume it's standard recreational use and the top rpm is between 5500 to 6000. Depending on what you're doing those plugs can be gapped anywhere from .030 to .040".
