If memory serves, there is a cold start primer under the starter. It would drain fuel from the top carb into the bottom two crankcases, to provide a choking action.
OK, lets just check the link and synch now. Remove spark plugs 2-6. Install them in their wires and ground their bases to the block.
put a timing light on spark plug #1 wire. Move throttle until carbs are ready to open, but closed. Turn ignition on.
Point timing light at black plastic flywheel cover. See thru window with needle, to timing decal.
Jumper starter solenoid and read timing light position on decal. it should read 0-8* ATDC,
Now advance throttle all the way. jumper starter solenoid and read timing light. It should read 21* BTDC,
Any deviation from correct timing can be caused by timing needle misadjustment (it happens) or by incorrect timing. Timing needle would need to be verified and timing would then need to be adjusted.
