Well I have a jp fx b5 and just trin to break it in but not havin any sucess. i heat the engine up to about 140 with a hair dryer cause it wont really get any hotter and i loosen the plug just a half turn and i try to bump it and it wont turn. i had it run for like 30 sec but otherwise i have torn up my bump box and dont know what i am doin wrong. I will also note i suck with the bump box, i am sure it takes getting used to cause it aint no pullstart. any suggestions would be helpful thanks.