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Throttle Opener System

With engine at normal operating temperature, check for loose, disconnected or deteriorated vacuum hoses and replace as necessary. Check that engine is idling at 800 ± 50 RPM (Man. Trans.) or 750 ± 50 RPM (Auto. Trans, in gear) with headlights ON. Disconnect vacuum line from intake manifold at control valve and connect directly to throttle opener unit. Engine speed should increase to 1500-2000 RPM. If engine speed increases but not within range indicated, check throttle opener rod for full movement (approximately.2"). If full movement is available, adjust stop screw to obtain 1500-2000 RPM. If full movement is not available, check for vacuum. If no vacuum is present, clean vacuum port at intake manifold and recheck. If full movement is still not available, replace throttle opener and recheck. Reconnect hoses and if necessary adjust control valve to hold throttle opener rod fully retracted for one to three seconds when throttle is suddenly closed from an engine speed of 3500 RPM. Adjust by loosening set screw and turning adjusting screw.

Fig 1: TESTING THROTTLE OPENER
G09355071Courtesy of AMERICAN HONDA MOTOR CO., INC.