Normally, the Tecumseh carburettor is stamped with a model number and date code. However, it recommended that the engine model number be used to look up replacement parts. If the carburettor number is used, it should be cross-referenced a parts manual.
Dual System Carburetors
The simplest way to identify the dual system carburettor is by the large primer bulb on the side. The dual system carburettor lacks adjustment needles. This carburettor is used on four-cycle rotary lawnmowers with a vertical crankshaft.
Series 1 and 2 Carburetors
There are variety of styles and applications of the Tecumseh Series 1 carburettor. This model is found on vertical and horizontal shaft engines of both two and four stroke types. The Series 1 carburettor is used on two to seven horsepower. The Series 2 carburettor is used on outboard engines. It is similar to the Series 1 except with a fuel pump and idle adjustment screw.
Series 3 and 4 Carburetors
Generally, Series 3 and 4 carburettors are used on four-cycle engines in the eight to 12.5 range.