have a problem with my honda not starting,backfired a few times when trying to start it,now will not fire or backfire.checked plug was carboned but visually ok,when turning over had vry week intermitent spark. WHAT IS WRONG? and what needs replacing? sorry the atv. is a Honda forman 400 4x4 blue factory color.dont know the exact year. probably late 90s or early 2000. thanks for any help you can offer......

 

I'd go ahead and change that spark plug if you haven't yet.

 

Thanks...that was the first thing I did......absolutely no difference.....any other suggestions? Besides taking it to my nearest Honda dealer?

 

Have you checked your timing yet? That will cause backfiring. Lean mix will back fire on deceleration as well.....

 

Try draining the carb.May be a screw on the very bottom of carb that you can unscrew a little to drain.May not be the problem but try it before you go to dealer

 

The carb is probably plugged up, and needs a good cleaning. Make sure to focus on the starter jet, and pilot jet, and youll probably find one of them plugged.

 

Yes, it does sound like you've got a dirty carb. Also, check to see if your choke plunger is sticking but most likely one of your jets is clogged. A blast of air will help.