I have a briggs and stratton 3.5 HP lawn mower and after 15-20 minutes the mower stalls and won't restart for an hour or so. I have replaced the plug, but to no avail.

Can anyone help with suggestions on what to look for now?

possible coil-- check with dvom to spec check valve lash hot---

if you have a condensor on your engine, it 's possible that once the failing condensor gets hot, it shorts to ground, thus preventing spark until it cools down. The condensor is a small silver can that's part of the ignition system.

this happened to me it might not seem like it but it is the carb clening it might not help but a new carb will

have spark in a plug or is a fuel problem. maybe only have the fuel cup hole block.

one thing on plugs don't use champion sparkplugs they are @#$%

im tellin ya either clean or buy a new carb it will run fine also is it a craftsman because their yard equipment is usually garbage but their tools r good but anyway i was working on 1 the other day and it had a plastic carburater which is sad

usually those small engines have plastic carb's to make the engine less expensive so it would be nothing to replace them. i had asked one time about replacing an all metal one on a riding mower no resemblance but it was about $190.00 thats why there plastic on those small ones. as for craftsmen mowers yeah there cheap but they have a fix it or replace it warrenty :D :D so if replacing the carb doesn't do it get it checked out

oh! try an autolite plug in it if you allready have one it might be the carb

is the mower green cause we had this happen on a green craftsman 3.75 with a b/s and it was the carb also is should be crapsman

Is it a pulsa jet carb or a vacuject carb....sounds like a carb problem but I would not hurry out to buy a new one

Sorry last post was for a Tecumseh but hope it helps someone out