There is a good possibility the vent was "clogged" so to speak...I had just filled at the gas station prior to launching that day and thought I had way less fuel in the tank than actually was.....had gas spittin' out the vent when I stopped filling. How does that come into play?

RWilson, I think Spare was trying to say that a plugged fuel tank vent coupled with the engine sucking fuel out of the tank would create a vacuum and prevent the primer ball from functioning properly.
I want to hear more on the dieseling theory. What would get hot enough in such a short timeframe to cause it, carbon, the spark plug itself? AND Would a lean run condition cause it to rev up worse? I know when I run my 2-strokes out of fuel the RPM's pick up just before they shut off.
Could the motor have been choked off by pushing the key in?
What a crazy thing. If that happened in gear, in Shem Creek, you wouldn't be able to take it out of gear and the results would have been interesting to say the least.

i had a Kaw 550 Standup that did that right often when the timing was off, i aways killed it but covering the carb so it got no air, it turned out the timing was off by 4* doesn't sound like much but it fixed it once timing was set.

motors won't do that under load the load kills them.

Do you agree that if it were caught early enough it could have been avoided? There was noone in the boat at the time the motor started to rev up.

Actually I had just pulled it in close enough to board when it started to rev up, and Rob was on pretty quick, just before it went bezerk and shut it down but it had no effect.
Thats when up in the sky what did I see? A bird, a plane, no, it's super Dave.

As it started to rev up, I thought it was fuel starved as Ridge mentioned and that it was about to shut down...but when it kept building RPMs w/nobody onboard, I started clickin' the shutter, cuz I was pretty sure SOMETHING was gonna happen and I wanted to document it, good or bad...glad it turned out good...there are a couple of shots in the sequence I didn't post..if anybody thinks they might be helpful in figuring out just what happened, lemme know and I'll post 'em all up...

I was going to comment about your pic sequence....here's my engine ready to blow and there's Reel playing Jimmy Olsen over there....click, click, click. I had no idea you were taking pics all along but it made for an awesome set of pics there.....Is that what you always do in times of emergency.....hey let me get this camera rollin!!:fam:

Reels trying to win Americas Funniest Video, figured he get a new boat one way or another

It started happening pretty fast...and I was too far away to get to it and do anything...and wouldn't have known what to do had I been in the boat...figured pics better than nothing...The right man got to it first no doubt...