Re: Mercury 4hp - Ignition Timing ??
Dartboy - this is assuming this is a 2-cylinder 4hp:<br /><br />Timing check:<br />Warm for 5 min. Throttle to 1000-1500 RPM. ATDC should indicate 18 to 20 degrees.<br />Quickly drop to idle. ATDC should go to 15 to 18 degrees as it reaches 600 rpm. Note the 600 RPM timing, and advance the timing two degrees, say from 17° to 15°. I just adjust the idle timing to get the best running myself.<br /><br />WOT timing should be set to 22° to 26° BTDC. WOT RPMS should be 4300-4700RPM, 6-700RPM in gear idle.<br /> <br />"Throttle primary pickup - 14°-+2° ATDC"<br />This is the point where the throttle plate on the carburetor just begins to open. You can amplify it's movement with an alligator clip with some stiff wire attached to it, clipped onto the carb throttle shaft. Setting this makes a _big_ difference in ease of starting. The cam that pushes the pin that opens the carb throttle has a little phillips screw on it's left side. Loosen to adjust the pickup timing. <br /><br />Hope this answers your question.
