Co2 extinguisher directed into tailpipe intake is a very good solution for any 'hot starts' and our recommended method to extinguish tailpipe hot start fires ....Forget about powder extinguishers unless no other type is on hand as the powder residue will get into engine bearings causing possible damage that can cause further serious problems and require engine to be stripped down fully and cleaned as well as bearings replaced.......Co2 is safe to use on all our engines with no damage to internal components.
Heres another neat solution to avoid the fire hazard - http://www.TJT.bz/board/viewtopic.php?t=71