Yamaha F100B F100C Outboards Factory Service Manual, Page 329Get this manual
Power unit Symptom: Engine does not accelerate when the throttle is opened quicklyThe engine turns off when the throttle is opened quicklyAcceleration is tardy and the engine is likely to stop at any moment Check the carburetors Check the ignition system Check the compression pressure of the power unitCheck the throttle cable operation
Do the carburetor throttle valves close simultaneously? Yes