We have a 17hp B&S that ran fine for about 30minutes then backfired and died. We can restart for a minute or 2 before the same thing happens again. I hope someone can help. The tractor is about 9 years old but hasn't been used as much as it should. It is in mint condition except for this problem.
HELP!! My husband is ready to buy new.

Can you tell me if it's a single cylinder OHV (over head valve, has covers on the front that's stamped ohv)
OR flat head? Apposed twin? V twin?
I'm leaning towards a carb problem, which is a lot cheaper then buying new to fix.

Ohv

Whens the last time the valves were adjusted?
I'd also like to ask if it starts right back up after it dies?

The mower starts right back up. Sometimes it will idle great and then shut down with a "bang". I don't know if the valves have ever been adjusted. We really appreciate your help.

Man that's weird.. the easiest (well if you have a thickness gauge and a few tools) is to adjust them yourself.
http://faqs.custhelp.com/cgi-bin/faqs.cfg/php/enduser/std_adp.php?p_faqid=3441&p_created=1101860144


The bang, almost sounds like maybe fuel being dumped into the cylinder at a too high of a rate... (which means carb rebuild)
But its weird to start right back up indeed.

Ok, adjusted the valves. Everything looks fine on them.Now it looks like its getting way too much gas and won't even turn over. What now? It acts like its flooding out.

OK, if it was getting too much gas... it would blow some black smoke.. is it indeed blowing black smoke? This would mean a carb rebuild... Because this may have a barely adjustable carb on it (epa regulated)

No black smoke. It won't even turn over now after the valves were adjusted. Could the adjustment be wrong? At least it was turning over before then. The only reason I say too much gas is because the person that adjusted the valves said that. My husband says it acts like its not getting any gas now.

Yes too much gas will give you black smoke... husband is right, it sounds like not enough at this point (which means a carb rebuild)

As for the person that adjusted the valves... I'm hoping this was a small engine mech? And you had a receipt? Because he certainly misadjusted them... that link above is the page that tells you how, and gives you a link to the exact specs...