I would first try spraying a little starter fluid into the carb and see if it starts. You may have crud in there. It would be unusual to have an engine running one minute and going to heck the next in this situation.

What do you mean "then backed the mixture screw back so the engine would shut off" Why would playing with the mixture make it shut off?

Where do I spray the starter fluid? Like where the fuel line attaches to the carb?

I backed the mixture screw as far as it would go, so it cut off any fuel or air from getting into the carb. I read to do that somewhere online here!

I honestly have no idea what's going on.

No spray it into the open end of the carburetor where the air filter attaches. If the carb is clogged it should only run for a few seconds.

Gotcha. I drained the carb of any gas so I'll try that cleaner and see what happens!

Damn, I feel like an idiot! I didn't end up using the starter fluid (although I still bought some just in case). I think the main issue was the battery! It was basically dead. Had enough juice to illuminate the dash, but not enough to turn the engine over. Plugged it up to me charger, installed in on the moped and voila!

I had a chance to mess with the carburetor... Is maximum idle when the back wheel starts the rotate? Somewhere online it said to match the idle and mixture screw to "maximum idle", then back the idle screw to a comfortable idle. Wasn't quite sure what it was getting at...

1-Turn mixture screw CLOCKWISE until it STOPS TURNING.

then

2-Turn mixture screw COUNTERCLOCKWISE 2 complete turns.

3-Start bike. (It may be necessary to adjust IDLE SCREW. to obtain useable idle.) Allow TEN MINUTES of running

4- turn MIXTURE SCREW COUNTERCLOCKWISE in 1/8 turns incremets until your RPMS reach MAXIMUM. then turn MIXTURE SCREW 1/4 turn CLOCKWISE. This is proper mixture setting.

5-Adjust idle screw until IDLE RPM is at 1800-2000 rpms.

I understand the above instructions, but my only question what IS maximum idle? This is all while the scooter is on the back stand, so the back wheel isn't touching the ground, correct...?

I read somewhere a solid idle setting is when the back tire barely starts moving, or enough to slightly engage the clutch... Thoughts? Is this maximum idle?

yes otherwise your belt will grab and when its off the stand it will want to stall and you will wear your belt out

Gotcha. Okay makes sense now. When I read "maximum idle" I imagined a scooter on a dyno about to fly off why they tune the carburetor haha! Let me tune the carb, ride around and check the spark plug and I'll let you know what I find (lean, rich, or optimal)

I'm still running a little lean, with a #90 main jet... I'm in Hawaii with an aftermarket exhaust, K&N style air filter, with 93 premium gas. Surely a #90 is sufficient?

Also I couldn't get my scooter to start again earlier today. I'm plugging up my battery to the charger as we speak. Anyone have any links to aftermarket performance starters? This is getting frustrating!

Talk to the people at www.partsforscooters.com they build drag scooters and might be able to tell you about starters on their chat.

a 90 should be plenty big.i would say keep adjusting your carb.my carb is richer to the left but guys on here will say different.lawn mowers,cars,motor cycles have always been like that but maybe that's just the usa

try putting some tape around your filter.after market filters are a pain in the ass

Okay so what EXACTLY does the mixture screw do? Literally, does turning it clockwise lean the mixture, and counterclockwise richens the mixture.