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Show GOOD POINTS ON SPARK CONTROL f Correct Ue of Lever Has ; Much to Do With Effi-ciency Effi-ciency of Machine. s Need the position of the apark lever 4 be changed, after the car la once well - under wayT That question occurs to not a few of the less experienced automobile drlv . if era during these days when operating 4 the motor car may be classed as one t of the moat popular pastime. Intelligent and correct use of the apark lever has much to do with the . efficient operation of a car and tends to Insure the proper functioning of the motor vehicle's Intricate and la many i respects delicate mechanism. Some car owners needlessly shorten the length of service they would get from their cars by carelessness in handling j the spark control. Don't Alter Position, i Except when going over unusually ' rough roada. there is no need to alter . f the position of the spark lever In ordl-. ordl-. , nary driving after It la once aet, since it is designed to run through a fairly varied range of speed. But In cllmb- Ing a stiff grade, most motorists speed .: their cars to take the hill with a ter- t fine rush because they do not want to shift gears. The euglne will atand this J buae for some time before It begins " k to make Its disgust audible with knocks ' and rattles. Knocks of a motor which Is laboring j In going uphill are due to premature i firing, the spark Igniting the gas on . the compression stroke ; the explosion 1 tries to force the piston head back be- 1 fore It has passed dead center, produc- : lag a sharp metallic tliump. , This would not occur, of course, on . t m level road unless the car were very .heavily loaded, since the crankshaft , revolve fast enough to bring the pis- f ton past dead center and on the down- -ward stroke before the pressure of the exhaust la effective, : i Should Be Advanced. . I At all times the spark should be ad- ff vanced as far as possible without caus- Ing the motor to knock j a spark which I Is slower than this tends to cause over- - I heating and carbonizing. The best and briefest advice la: Get acquainted I with the sound of your motor and ad- 1 just the spark accordingly. |
