i have 2 of these engines , awesome work of art and power for price. my advise is just follow the manual. no need to pre heat the engine what so ever . and if u ever open the engine up dont try to push ur piston trough the liner . it will go right threw . when these engine are cold they seem not to have any compression or very less. but that's what special about these little power packs . never let the engine run over 120 degree cel. and the gearing on this engine are set a bit differently .
cheers alex