Re: timing a 1500 tower of power
Engine off
Disconnect throttle cable
Pull throttle arm to full throttle and verify carbs open fully. Adjust main throttle stop so that the carbs are JUST hitting thier own little throttle stops. The idea here is that you want the screw stop and NOT the carbs acting as the "final stop" for your throttle lever.
Return the throttle to idle, carbs should be closed. Set all idle screws to 1 3/4 turns out from lightly seated.
Remove all plugs except #1, hook a timing light to #1. Then follow the narritive.
When the throttle is in the idle position the carbs should be fully closed and the ignition retarded. It is the amount of retardation that determines your idle speed and is set later with the idle stop screw.
Timing Event One - throttle pickup.
As the throttle is advanced, the spark timing advances toward TDC and then to before TDC. As the timing is just passing TDC the 1st (minor)throttle pickup should hit and start to open the carbs. Use the timing light. Adjust the tang or trigger screw to make this a reality. All of them are speced different, but if the 1st pickup hits at 3-4 degrees BTDC advance - you win. Use the timing light with a friend cranking it to complete this setting.
Timing Event Two - max advance.
As you continue to advance the throttle the timing will advance while the carbs slowly open a bit more. The next adjustment is max advance, this is the point where the distibutor (or trigger) can advance no more. Set the max-advance stop to 21 degrees.
Right after max advance, further throttle motion should cause the second throttle pickup to hit and open the carbs to full. Thanks to Clam Canino for this info.
Nowhere is there anything mentioned to set the timing @ 21 degrees BTDC @ WOT (wide open throttle)
