BRIGGS & STRATTON SONODUCT ENGINE 1959-1962?
These engine were enginered to reduce noise. The flywheel and coil where taken from the top and put on the bottom. This allows the deck to be used as a noise suppressor. The engine was enclosed in a box for further noise suppression. Although it was and enginering marvel for its time, it ended up a complete failure. It was manufactured on a limited basis. The main problem is that it was not practical for lawn mower manufacturers due to it needing a expensive, special built mower deck to mount it on. The bulk of these engine were sold to laawn boy and J.C. Penny's. Briggs eventually recalled as many of them as possible.
Briggs & stratton 3 HP vertical shaft gas engine 1963
This engine went into production in 1955 and it still in production today. It has gone through lots of changes in carburation and ignition. The looks have changed some but it is still the same basic engine that replaced the small cast iron engines in the 50'S.