Sounds like you blew the engine up. If you want to fix it you'll have to strip it down completely to find the problem, could be a cracked piston or timimg gear or broken valve, or cracked piston ring or broken connecting rod. You wont know untill you take the crank case off, maybe its fixable with a bit of time or money.
if the cylinder block is cracked then your rooted.
FOLLOWUP:
Deejay or anyone, any info an getting these rods and springs for the B&S engine Model 802xx with piston type choke/carby unit.
if you got a parts list go to you local lawn mower store.
or
http://www.jackssmallengines.com/ or
http://www.rcpw.com/for B&S engine parts