Check the brand of engine they use to begin with. Then pull and start them. You can tell a lot by how easy they pull and start. I have a John Deere that we use and if I didn't know better, I'd swear it was a Honda, may have been made by Honda for JD.
I also have a 5000 watt electric start Honda that has given me more problems than my JD, which has had none.
Smooth Smoke BBQ Team, KCBS CBJ, 2-WSM, Cajun Bandit Conversion, wsm 2880, Smokey Joe Mini wsm, Old Country offset, several kettles.