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I'm new to the scooter world and not much of a mechanic so just looking to clear up some confusion.  I've been without wheels of any kind for close to a year now and it really sort of sucks.  My uncle recently dropped a couple of Chinese 50cc scooters off for me to tinker with and try to get running.  I'm still on the first one and here's the story so far.

New battery and fresh gas lead to nothing.  She turns and turns and turns but never fires up.  I finally worked up the courage to strip her down and try a carb clean after watching a few YouTube videos to find out it's not as scary as I thought it'd be.  I got all the necessary fairings off, pulled the fuel and vacuum lines, unplugged the electric choke from the bike, then pulled the carb.  Much easier than anticipated and I'm loving working on this little guy more than I ever cared to work on my cars.

I got it open and the gas inside was vile.  A dark, murky brown mess with water in it as well.  I pulled the gasket up, it's still soft and fresh somehow (this is a 2004 bike that's barely been driven, just sat,) got both jets out and the float off.  I sprayed the jets out with carb cleaner and shined them up and they seem nearly good as new now.  I hit the float (the metal pendulum bit, not the plastic bits,) with cleaner, filled the carb up and let the jets and screws soak, scrubbed it all up and put it back together.

I put it back on the bike, hooked it all up, tried to fire it up and BANG, she lit right up like nothing... then stalled out and wouldn't try again until I left her sitting a few minutes.  Then again, starts right up then stalls.

My research tells me it could be the carb needs a better, longer soak (other small inlets/outlets other than the jets that might need more cleaning,) or replaced.  It's a $25 part, so I just ordered it and it will be here Friday.  It works, awesome, not, we'll go from there... but here's the confusing bit... I researched my bike and found that it's listed as a 2-stroke when the carb I ordered, completely identical in every way to the carb in the bike, is a 4-stroke.

This is the carb my research says should be in the bike here but what's actually there is a spitting image of this.  Now, the bike on the left in the comparison at the following link is the closest thing I can find from the manufacturer to what mine looks like, but the bike on the right is an absolute spitting image other than mine's red. See here.  Mine, in appearance, is a QM50QT-3E(AG) and is listed as a 2-stroke.  The only 4-stroke models for that year are the QM50QT-6S (shown in the last link,) and the QM50QT-6V which looks NOTHING like my bike.  The 4-stroke carb I ordered appears identical to what's in mine other than the cap on the top is black plastic presently and a brass look on the one ordered.

My main question is can you run a 4-stroke carb in place of a 2-stroke all willy-nilly or is it possible some fairings were changed or a different engine put in somewhere along this bikes way?  The odometer reads 181 miles and I'm prone to believe that's all it's got on it.  The airbox is ridiculously clean, the carb was even far cleaner than I'd expect to find on a bike sitting as long as this one and that is as old as this one.

I'll follow up with some pictures once daylight comes if it will help any, though she's all torn down right now, so we'll see.  Any help is greatly appreciated.