I'm too lazy this morning to look it up, but as someone who sat in the Kingdome and watched Dave Krieg a lot during his career, I'll bet he was way up on the "most career fumbles by QB" list as well... Krieg dropping back, getting sacked and coughing up the ball was a sickeningly regular occurrence.
153 career fumbles, placing him
second third, behind only Favre at 164
and Warren Moon at 161. It should be noted that Favre does have almost 100 games more than Krieg, so in terms of fumbles per game for starting quarterbacks, he's probably way up there.