2005 Ski-Doo Racing Handbook, Page 138Get this manual
SECTION 05ENGINE PREPARATION
Exhaust Gas Temperature Probe Location
A00C3WY
Detonation720C (1330F)
1100 mm from piston 2Probe
NOTE: Temperature at wide open throttle at maximum HP RPMExhaust gas temperatures (E.G.Ts) can also give an indication of mixture ratioAt wide open throttle (W.O.T at maximum HP RPM, leaner mixture will produce higher E.G.Ts and richer mixture will result in lower E.G.Ts(E.G.Ts are not absoluteEngines have seized with E.G.Ts in the allowable range)
Air entering the bell of the carburetor has speed of V1 and pressure of P1As the air is forced into the smaller diameter of the venturi, speed increases (V2) but pressure drops (P2)Passages in the carburetor connect the venturi to reservoir of fuel (float bowl)The float bowl is vented to the atmosphere (P1)P1 is greater than P2 so fuel is pushed from the bowl to the venturi via the jets and passagesVarying the size of jets varies the amount of fuel the engine receivesEngine speed is controlled by varying the amount of airfuel mixture that the engine receivesLiquid gasoline does not burn, so for the engine to run efficiently, the fuel must be broken down into small droplets, and mixed with the oxygen molecules in the incoming airThis is referred to as atomizationThe shape of the venturi and the shape and location of the jets and fuel delivery passages will determine how well the fuel and air are mixed