Recently rebuilt my B&S Quantum 5hp engine. Model 124712, type 0121. Quick breakdown: Initial teardown, inspection, cleaning, etc. Rebuild. New gaskets, rings. Engine becomes hard to start, but not severely. Perhaps an extra 3 pulls. Winter. Brr. Don't mess with mower till Summer. Partial teardown due to head gasket misaligned, replaced valvetrain (springs, keepers, valves). Engine is rediculously hard to start. Excess of 20 pulls, only cranks when it wants to. It cranks up fine if its warmed up, but it's a bear when cold. Throttle is also weird, used to throttle down to idle just fine, but now midway on the throttle control and it stalls out. WOT RPM is low, I don't know exactly since I don't have a tach but I can hear a difference. Tried adjusting carb needles, gov. linkage, and compression aid (oil in cylinder to help build up compression). No go. Any thoughts? Did I overlook something?