Modern Vespa

When the carb is set up right, which it seems to be very close to now, I do not normally have starting problems. I will use the electric start to crank a stone cold engine just because a couple of seconds of the electric will always get it going on one try, but after that I'll kick it the rest of the day to save on battery and starter wear and not have any difficulty.

So yesterday I'm on a longish 60 mi ride in the pseudo-countryside and reach the end of the pavement where it turns into a gravel Y-junction in the middle of nowhere. I pull out into the wider gravel area and shut it down for few minutes to look around and take a picture or two before turning around. Ready to head back I start to turn the bike around by foot (mistake) and my foot slips and it very nearly drops on its left side. I managed to save it, but it was leaned waaaay over to the left for about 10 seconds while I struggled to regain my footing and set it aright.

Angry with myself for nearly dropping it, I go to kick start it and .... nothing. It won't start. Not with the electric, not by kicking. I double checked kill switch, ignition switch, fuel tap, at least 1/2 tank fuel. No sputtering, just nothing like there wasn't any spark. Thinking this can't be happening or maybe it somehow flooded, I probably kicked it about 20 more times when it briefly sputtered a few times, but still wouldn't run. With hope in sight, I kicked it about another dozen times or so when I was finally able to nurse it alive with the throttle, but it did not want to run at idle. Turning up the idle a bit seemed to keep it going. After heading down the road it seemed fine, but I later noticed the idle was now too high so I turned it back down. There's been no other issue since.

Before anyone asks, no, I didn't pull the plug or check for spark. I was just about to do that when it starting sputtering, so I kept going with that.

What has me baffled is, why would being nearly laid down on the left side cause a symptom like this? I would think being on the right side might flood it, but not the left.

Any ideas or similar experiences?

Maybe it was an air lock in the fuel supply?
Coupled with possible loss of fuel from the carb bowl?
No harm done.

I figured it was okay, I just couldn't figure out if it made any sense or not. I wondered about fuel draining back into the tank also, but didn't see why it wouldn't flow right back into the bowl once righted. Yeah, maybe an air lock, or maybe the float hung up on the side. Just wondered. No biggie.

Methinks you're wondering too much

the carb float bowl has too much fuel in it resulting in a way too rich mixture to idle or for engine to start with out doing 1st a few simple tricks...

If this happens again all you have to do is turn OFF the fuel tap, hold throttle open all the way (WOT) and start engine either way you can. Once running hold the throttle @ WOT so that the engine can get as much air as it can until the float bowl's fuel lowers to the correct fuel height.

might take a minute

once engine rpms shoot up = turn fuel tap back to ON or RES

you can also fix this by
- turning tap OFF and lean whole scoot over to the side so fuel can flow out the carbs overflow hole. Then repeat the above steps. Should take even less time to be back on the road.

If the float is sticking this is how you fix it (along with bouncing the whole scoot up and down). The float needs to be jared so it "floats."

Of course!
Its late here!
When this happened to me (flooding the float bowl chamber) i used to kick it over with little throttle through fear of fouling the plug.
Its also a reason that i think those carb bowl spacers are a bad idea. (by essentially raising the fuel level).

I would think that the fuel in the bowl would have drained into the crankcase and got the plug pretty wet. This would always happen to me when I trailered the scooter with a full tank... you could only ever push start it after that.