spun timer base - close call

On my E50BELCO.1985 - Took it out for the first test run and couldnt be happier...ran like a top. Prior to that I had to change to timer base because the old one had bad bushing and there was evidence of contact. Anyway - got it all together- test ran at home - all good...ran on the lake for 20-30 minutes - all good...beached it, backed the trailer into the water, went to start it again and 1/2 a rev then *click*. - First thought - overheat and locked - few cusswords, pulled cover - not hot at all. tried to spin flywheel by hand and wanted to turn but something was physically stoppin it. trailered it got home and ill be damn if the one of the screwheads that hold the sensor (#4) to the base had come completely off and caused contact underneath and gave it a good 1/4 turn beyond the stop. bent up my linkage and the advance stop tab. Luckily it was while trying to start that it happened or lots more cusswords would have happened then... No wires pulled out or other damage done - had new linkage and bushings to put all back together withing 20 minutes or so.
The moral - I dont have one I guess - just double check all that old hardware - It sure seemed fine when I tightened it all back down. all the vibration and heat from running caused it to give I guess. Im lucky - things couldve been a lot worse if that had happened at full gallop..

Did just the head come off or did the whole screw come out ??

Just the head...very strange. Never seen that happen before. As soon as I pulled the flywheel off, the head fell right out. The shank of the screw was still flush with the top of the sensor mounting hole. other screw still tight. the sensor is below the level of the stators so nothing came into contact with it.. You can see where the head came into contact with the stator pickup head. Ever see this happen? Again very thankful it only happened under power of the starter...not at 4000RPM.