Tecumseh Parts    |    Tecumseh Parts Lookup    |    Tecumseh Repair Manuals SERVICE BULLETIN 107 INFORMATIONAL ISSUED: May 1970 REVISED: June 1995 SUBJECT: Revised Safety Specifications for Rotary Type Power Lawnmowers MODELS OR TYPES AFFECTED: All Tecumseh engines used to power a rotary type lawnmower. The United States of America Standards Institute, sponsored by the Outdoor Power Equipment Institute has recently revised the maximum blade tip speed of 21,000 Ft./Min. downward to 19,000 Ft./Min. As blade tip speed of a rotary type lawn mower is always in relation to engine RPM, it is extremely important that before delivery to an owner the maximum RPM is set so the maximum blade tip speed will not exceed the new 19,000 Ft./Min. specification. The following chart gives the maximum blade RPM which will produce a blade tip speed of 19,000 Ft./Min. for the various blade lengths commonly found. BLADE TIP SPEED BLADE LENGTH BLADE RPM BLADE T

DIAGNOSTIC CHART Normal   (Life in case of normal use)                 A worn spark plug not only wastes fuel but also     strains the whole ignition system because the     expanded gap requires higher voltage.     It also reduces the engine's efficiency, resulting     in reduced fuel economy and increased exhaust     emissions. Moreover, it contributes to pollution Using Unleaded Petrol   generated by exhaust gas.       SYMPTOMS     CAUSES   REMEDY               • Hard starting       • Rich mixture   • Check float level • Misfiring   CARBON   • Retarded ignition   • Check choke • Black exhaust smoke     • Low compression   • Check ignition timing     FOULING   • Too cold a spark plug