On a 120 or smaller engine,I cut the space to mount the engine on a 1x4 by a couple feet long,bolt or screw the engine beams to the cut out mount,add a tank behind the engine,and a long wire for throttle control,bolt the board to a table top or something sturdy, leaving the engine and prop clear of any objects,on large glow or gas I do the same only using channel metal with the holes precut.