You guys ever run Marvel mystery Oil in the fuel?
I've heard guys tell me it's great on these.

 

Wow, that took me back. My father used to use that stuff all the time. We're talking 25 some years back. I believe (IMO) this stuff is like seafoam. I can't remember of any problems all those years ago and I've used seafoam in many of my vehicles over the last couple years. Never on the hawk though. Not sure why. I guess maybe I'm worried about fouling a plug. They're a pain to change. When I use it, I use a vacuum line and eventually stall the engine w/ it, let it sit several minutes then fire it up. The smoke is pretty bad but it's supposed to blow out carbon deposits.