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ENGINE ELECTRICALTypical 19<strong>85</strong> - Current Timing Advance CurvesIgnition TimingMAXIMUM ADVANCEOPERATINGRPM(DEPENDINGON ENGINE)SEE DATA1000 2000 3000 4000 5000 60007000 8000RPMNOTE: Always verify timing of <strong>engine</strong> at room temperature only (68 0F/20° C).The ignition maximum advance is at or near 3000 RPM on all current style ignition systems. Verify the ignitionposition at maximum advance when checking the timing.If <strong>engine</strong> damage has occurred due to a suspected ignition related problem, check the ignition timing at thespecified operating RPM.Due to differences between <strong>engine</strong>s, it is necessary to dial indicate the timing marks on all <strong>engine</strong>s beforeattempting to adjust the ignition timing. To indicate the marks:1. Remove the mag cy~nder spark plug and install the dial indicator.2. Rotate the cranRsbaft by hand while observing the dial indicator. As the piston touches the indicator plunger,the dial will begi~tO'rotate. Find the pOint where the pointer stops rotating and reverses direction. This will beTDC (Top Dead Ceri'mJ").3. While holding the crankshaft with the pi~ton at TDC, zero the indicator by rotating the bezel until the 0 on thedial and the pointer align.4. Rotate the crankshaft opposite the direction of rotation about .250 BTDC (2 1/2 pOinter revolutions).5. Determine the correct ignition timing position fromthe ignition data charts and rotate the crankshaft inthe normal direction of rotation to that position.(Example: 1993 EC50PM-01 <strong>engine</strong> timing is.150 BTDC. The crankshaft must be rotated in thenormal direction of rotation so that the dial indicatorpointer does one complete revolution and stops on50. This should be 1 1/2 pointer revolutions beforetop center, or .150 BTDC..I'6. While holding the crankshaft at the correct timingposition, determine which of the rotating andstationary timing lines align. Mark these lines withchalk or a marker to make them easier to identifywhen you are doing the running timing.8/94 4.12