Scooter newbie having 50cc revving problems....

[laterider]

Hi there,

I’m new to the forum, but have been nosing around a bit hoping that I could find an answer to my problem. I did see that someone on the site had a similar problem and the thought was that maybe there was a torn or broken diaphragm in the carb, but I’m not sure about that here….I have a 2008 Motobravo 50cc scooter with about 2300 miles on it. It has your basic GY6 engine setup in it. It’s been driving fine all summer, until about a month or so ago when my wife took off to go to work and the engine just died. It would start and then die. She ended up having to walk it home and I took a look at it, and fiddled with the carb a bit and got it to at least idle. But give it gas and it barely revs any higher and sounds like it’s struggling to get enough air. Or maybe it’s not getting enough fuel. I ended up changing the spark plug, fuel filter, bought a replacement carburetor (I was going to pull it and rebuild it, but the replacement was only $25, so I figured that would be easier. I’ve replaced the CDI and ignition wire this year already. Cylinder head compression is about 120 psi. When I began work on this scooter, I noticed it was really low on oil, so I changed it, and it’s now back where it needs to be. And when I run the engine, it sounds okay, but when I rev it up, it sounds like there’s a “squeaking” noise, kind of like the noise a loose fan belt makes, but other than the drive belt, I don’t think there’s such a belt in this engine at all. I’m sure I have all the vacuum hoses attached properly, and I’m wondering if adjusting the valves would help (it’s never been done to my knowledge) or is this engine just plain cooked? Any ideas?