Modern Buddy

Thanks in advance for helping me with this issue.

I just bought my first scooter for my wife, a 2003 Stella 2T from Ebay (I know, buyer beware). The seller had good feedback and told me there were no mechanical issues.

I picked the scooter up today after shipping it from MI to TN and was very impressed with the cosmetic condition, and that it started right up (no choke). I rode it about 5 miles to work with no problems and a big grin, parked it for about 30 minutes, then drove it the 2 miles home. On my way home, the scooter died within 500 yards of the office as i forgot to turn the fuel switch back on. After turning it on, it started right up and i was on my way. A couple of minutes later, the engine started revving really high independently of the throttle handle. I would pull the throttle all the way back, take my hand off it, and it would continue to run. The only way to get it to stop that I found was to shut the engine off and re-start the bike. I eventually got the bike the 2 miles home from work, but this happened maybe 5 times on the ride.

The issue seemed to be initiated by changing gears. Now, this is my first scooter but I have driven manual transmission cars for years and was very careful to fully release the throttle when changing gears.

Has anyone had this problem or know what I could be doing wrong?

Thanks again,
Ashley

hmm, either your throttle cable is sticking (unlikely since shutting off fixes it, does the throttle closes itself when released?) or your engine is dieseling. Does the engine die immediately upon shutting off or does it keep running for a while?

If it keeps running it's definitely dieseling, this can be caused by a few things such as: incorrect timing, engine running lean, having the idle speed set too high, carbon buildup in cylinder or a malfunctioning carburetor, . Those are the common causes off the top of my head.

Sounds like you have a vacuum leak. Mine did the exact same thing. Turns out the gasket for the intake manifold was flawed (or put on improperly... I did buy it slightly used with 200 something miles on it) and allowing air to pass. That will cause an out-of-control throttle that requires a punch of the killswitch.

Yeah...classic symptoms of an air leak. Retorque the head bolts, check that the carb is secure. To me is sounds like fly side seal...don't panic....not a big deal to replace.

I had the same problem except with mine even switching the ignition off and removing the spark plug cap wouldnt kill the engine (in hindsight I should of just switched the fuel off)

With mine the problem turned out to be the reeds. I was running red polini carbon fibre reeds and after about 4000 miles they had weakened and weren't fully closing causing the engine to over rev.

I switched back to the standard reeds and the problem was solved.

To rule out an air leak,locate the 'air mix' screw on the back of the carb, it should be hidden behind a plastic or rubber bung.Remove the bung and turn the screw all the way in (not how many turns it takes so you can re-set it) if your engine dies you dont have an air leak, if it keeps running .......... you do.