I've got a few year old (5) br400 back pack blower that is always giving me grief. Sometimes it will run fine for 2 or 3 hours then just quit and wont restart. sometimes its only 2 minutes. My dealer refuses to beleave it's a electrical problem and has replaced the fuel cap. I think its something in the coil. Does anyone have a similar problem or any advise? How much is the coil to replace or is there a better coil out there?