I'm using an onboard glow driver made by RAM electronics, the Ram 50 to be exact. It has a C-cell, 1300Mah nicad and supporting electronics that hook to the throttle servo using a Y-adapter. You set it up to cut on at idle to keep the plug hot. It serves two purposes; it keeps the engine idle at low RPMs for reliable which allows for better reliability at low RPMS, and you also use it instead of a standard glow driver for starting. It works great. I can get my OS120 pumper to idle very nicely. I'm using these on all my larger 4-stroke engines.

Steve