Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

11HP B & S engine backfires through carb.

evetheodis's Avatar

Join Date: Aug 2008
Posts: 1

08-22-08, 11:33 AM   #1  
11HP B & S engine backfires through carb.

I have a problem on a riding mower with a 11hp B&S engine. It was running fine then just died as if it was shut off.
When I try to start it now, it actually backfires through the carburator. The mower is getting spark and fuel. I checked all the basic stuff and even replaced the plug, float and needle valve. Results are the same, while it is cranking it backfires through the carb.
It even caught fire once when it backfired.. Any suggestions?

Last edited by evetheodis; 08-22-08 at 11:34 AM. Reason: more info added
Sponsored Links
CPeppy's Avatar

Join Date: Dec 2007
Posts: 26

08-22-08, 12:37 PM   #2  
Maybe pull the head off and see if a valve seat popped out of place.

30yearTech's Avatar

Join Date: Oct 2006
Posts: 1,176

08-22-08, 04:45 PM   #3  
Post your engine model, type and code numbers please.

How is the oil level in the engine?

Was the fuel you were using fresh?

There could be a problem with a sticking intake valve, or valve seat as CPeppy advised.

ecman51's Avatar
Banned. Rule And/Or Policy Violation

Join Date: May 2007
Posts: 8,629

08-22-08, 05:31 PM   #4  
Or that some tiny eyeglass sized throttle plate screw did not vibrate out and fall into the intake port, and is either lodged between valve and seat, holding the valve slightly open, or is floating around in there, and may even be hiding in there one minute and lodging the next.

Search this Thread