Re: Tach dosen't go to 0 when motor dies
The zeroing of the tachometer is not acomplished by a lack of ignition as the voltage is still being applied to the tachometer (key on).<br /><br />It is activated and zeroed by eliminating the circuit (key off), then reactivating the circuit (key on).<br /><br />You might compare the circuit with the S.L.O.W. circuit. It also cannot be reactivated unless the circuit is eliminated (key off - key on).<br /><br />The idle problem... Have you checked the compression on all cylinders? What are the readings?<br /><br />With the s/plugs removed, the spark should jump a 7/16" gap on all cylinders with a strong blue lightning like snap. Does it?<br /><br />If the above two areas are as they should be, the idle problem is usually due to fouled carburetors (common if the engine has sat for a few months or so). Or the idle may simply be too low. On a flushette, the idle rpm of a 20" shaft engine should be 1000 rpm, a 25" shaft 1200 rpm.<br /><br />You can check the carbs by having the carburetor face plate off, the engine running at idle, then one carb at a time... srick two fingers into the carb throat (acting as a manual choke). If the rpms increase and the engine smooths out somewhat, that carburetor is fouled and will require cleaning and rebuilding.
