What would cause this?

[tt_four]

I'm putting this here because it's not really GS related. I've been trying to fix up this moped that my wife brought home a couple month ago that was in awful shape. I'm about 98% of the way there finally. I can get it to start, and run if I'm very careful, but here's what it's doing.

I start it up, and it idles just fine, although a little fast, but no biggie there. If I try to even touch the throttle it starts to sound like it's going to die, but if I let off fast enough it'll go back to its high idle fine. However, if I just twist the throttle wide open, it sounds like it wants to die for a split second, but then it revs up past that just fine. The motor still feels pretty weak(I know it's only 50cc, but it feels even weaker than that), but it atleast runs. I haven't tried to ride it very much, just up and down the block once, but at one point I did try to ride it up a decently steep hill, and it got half way and just died. It's a pretty simple setup. One cylinder, no valves, I don't even think the carb has an idle adjuster.

Any ideas? The gas in it has been in it for about 2 months, so I plan on atleast changing that out for some fresh gas, and I just replaced the sparkplug.

Anyone have any idea what might make the throttle sensative at low rpms, but finally pick up if I really twist it? I assume the two issues between that and the motor feeling weak could be completely seperate things, but who knows. I did just replace the spark plug, so after I run it for a little while I'll put that out and see if I can tell anything from how it looks.

[intergalactic]

I vote for a part clogged pilot. The accelerator pump gets you thru if you juice it, but not with a roll on. Sounds like my automatic choke Honda outboard.

[yamahonkawazuki]

I vote for a part clogged pilot. The accelerator pump gets you thru if you juice it, but not with a roll on. Sounds like my automatic choke Honda outboard.

YUP pull the carb, soak and clean it THOROUGHLY

[tt_four]

I did clean it very well, but I don't have a problem doing it again just to be sure. There's only one big jet in it, so I don't believe there's actually a pilot jet to be clogged, but I'll check and make sure there's no little holes in the carb body somewhere that might be closed.

The only reason I like complicated machines is because when something brakes, I feel ok about not knowing what's wrong with it. I hate looking at something with 3 parts and still not knowing what I'm missing.