Arghh!! Vespa Si will idle fine, not run

After cleaning the carb, checking the spark plug, etc. my Vespa Si still won't go forward. It'll idle fine (although i walked it off a curb and it stalled...clue?) but as soon as I twist the throttle (which in turn disengages the choke) it dies. A few times it accelerates for a few seconds, but mostly it just stalls out immediately.

Any ideas? The throttle? Electrical? HELP!! Thanks a million...

Re: Arghh!! Vespa Si will idle fine, not run

Bruce Wilkinson /

Do you have the airbox on ? Did you take the brass jet out and poke a wire through to clear it ?

Re: Arghh!! Vespa Si will idle fine, not run

Bruce Wilkinson /

You think the muffler is clogged ?

Re: Arghh!! Vespa Si will idle fine, not run

the airbox was on while this was happening...yes. I did not take the jet out and poke a wire through it...I couldn't figure out how to remove it. The brass screw at the top of the tube come out, but the jet seems to be way down in the cylinder (the tube) with no way to remove it. I'm sure I'm wrong.

I haven't checked the petcock to see if that's clogged. Could that be it? Should the fuel line be totally filled with fuel when the valve is open? Right now when I open the valve it fills about 1/3 of the way. Should it just be gas from the tank to the carb?

not sure about the exhaust. I'll check that.

Re: Arghh!! Vespa Si will idle fine, not run

Leon Swarmer /

will it rev up just sitting on the center stand?

Leon

Re: Arghh!! Vespa Si will idle fine, not run

on my vespa moped, the jet comes out of the bottom of the carb when you unscrew it with a flathead screwdriver.

Re: Arghh!! Vespa Si will idle fine, not run

Bruce Wilkinson /

That brass screw at the bottom of the tube IS the jet as nate said. I would drain the gas tank into a container, remove the petcock, flush the gas tank out with the gas into a glass bottle with a coffee filter on top to catch the rust.Do this 5 or 6 times. I'll bet a ton of rust comes out.Clean the petcock with an old toothbrush carefully.

Get an inline fuel filter at Home Depot or Canadien Tire and spice it into the fuel line so it traps any rust from the gas tank.

And clean the carb again.

Re: Arghh!! Vespa Si will idle fine, not run

to answer your questions 50plus, no it wil not rev on the center stand. I twist the throttle...then kaput.

So, to clear the jet I poke a wire down into that hollow tube?

What's your advice on how to drain the tank? It's full currently. Do I siphon it out?

Another quick one: How do I get at the wire connecting the tail light to the rest of the bike? The Frame seems to be a contiguous piece all around that area...I can't think of anyway to access the wire...and I have reason to believe that it might be broken (the guy I bought it from thought that for some reason). I'm talking about accessing the hollow part of the body under the seat.

Thanks. You guys are incredibly helpful.

Re: Arghh!! Vespa Si will idle fine, not run

Bruce Wilkinson /

The jet is the nut like thing that you can undo with a flathead screwdriver.

Turn off the petcock. Undo the banjo at the carb.Put end of hose in a big enough container. Turn on petcock.Do this over cement not asphalt.

I'll have to have a look to see where the wire goes.

Re: Arghh!! Vespa Si will idle fine, not run

Does it have an air filter? My bravo was doing the same thing and it turned out that the engine wasn't getting air because of a dirty filter. I'd check that first..

Re: Arghh!! Vespa Si will idle fine, not run

Leon Swarmer /

And be very gentlel when putting it all back together it's very easy to strip the threads holding the banjo on.

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