I experienced a problem where my 2007 49cc Triton Li would mis-fire and stumble when the throttle was fully open. I traced it down to the NGK Iridium (BR8HIX) spark plug. No improvement with cleaning and re-gapping the plug. The problem was cured by re-installing the factory original BR8H plug. I was wondering what the life of this type of plug is in a two cycle engine? I've got less than 950 miles on the plug. Also I gapped the plug at .028. Is that a good setting for this type of engine?

Regarding the carburator, while working on the scooter I noticed a thread hole on the top of the carburator. It runs vertically above the idle mixture screw and doesn't appear to serve any purpose. In viewing the on-line carburator photos in the FAQ section of this web site, it would appear that the threaded hole was originally covered by a plastic stake plug. I'm I correct in my assumption? For now I have just threaded a bolt into the hole to keep dirt from accumulating.

Any advice will be most appreciated!