1/5 KM baja buggy engine problems please help
 

My engine keeps quitting on me as im running my buggy and as it does the pullstart string cone all the way out and gets stuck. I replaced the pull start with a easy pull start and aluminum pawl and a new flywheel and its still happenjng. can anyone help me please. Its bugging he crap out of me and i really want this problem fixed. Any help would be greatly appreciated thanks.