Recent work in connection with the Cooperative Fuel Research is discussed in the paper, which presents data obtained as a result of the recommendation of the steering committee “that the factors contributing to easy starting be investigated.” It refers first to preliminary work discussed in previous reports, and then describes the test set-up. This was much the same as that used in the crankcase-oil-dilution tests, the chief difference being the replacement of the carbureter by a single jet mounted in a vertical pipe. The arrangement was such that changes in jet size, jet location, rate of fuel flow, throttle opening and choke opening could be obtained easily. Provision was made for measuring the amount of fuel used in starting.
The test procedure consisted in driving the engine by the dynamometer until conditions became constant, then in turning the fuel on and noting the time required for starting and the amount of fuel used. The information thus obtained is presented in curves and its significance is discussed. Among the factors the influences of which are shown are fuel-air ratio, jet size, jet location, spark-advance, fuel volatility, amount of throttling, amount of choking, temperature of jacket water and temperature of entering air.