I am trying to set the timing on my merc 850 SN4720922. This is the one without a distributer. I am supposed to advance the throttle arm till the primary pick up cam just touches the carburetor tab. The problem is that on my motor, it barely touches the carburetor and NEVER moves the carbs. The carburetors don't start to open till the secondary cam comes into play. The buterflys in both carburetors are fully closed till the secondary cam starts to open them. So where should I have the throttle lever when I set the primary timing pickup? The primary cam does just touch the carb tab, but not enough to start to open the carburetors.