valve adjustment

If you are having trouble with you overhead valve Briggs and I suppose others, kicking back or not wanting to turn over like a bad battery, check the valve clearance first. Loose valves on these engine can cause catastrophic disassembly. 

Amazing more people don't know that isn't it? What happens is by getting the adjustment too wide it takes the over lap out of the valves and raises the comp. Briggs has weird valve configuration anyway so that comp. can go wild. But you sure are right they are touchy. Leon R  Cmo

I had a rocker break on mine last year. Got a new one and put it on, making sure the clearance was right for that engine and it started up and died in about 5 seconds. The new rocker was broken. I called a local lawnmower shop and he asked me to bring the head in.
 I took it off and brought it to him and he showed me in 2 seconds what the problem was. The cast guide in an aluminum head came partway out. Enough so it would tip and bind on the valve stem if it wasn't setting perfect. I got a new head and she's been running great ever since.
 A note to remember; EVERY time you finish mowing, use compressed air to clear out any debris on or around the block. If that head gets a bit too hot, the aluminum head can grow faster than the cast iron guide and you got trouble.