Vespa Grande not starting. dripping fuel.

diggum seattle /

Hi everyone,

Thanks for the advice in the past. I've had this '79 Grande running very nice!

However...

Suddenly, as I was driving my kid around a parking lot, it died. I figured it was out of gas, so we rode home and filled up, but no luck. Won't start, drips gas when I try.

So here's what I know:

- Not seized. Good compression.

- Getting plenty of gas up front. Filter is good.

- Good spark.

- I MAY feel some air escaping through the decompression valve when closed. I'm not sure yet. disconnecting the decompression cable and manually decompressing during start attempt didn't make a difference.

- Gas appears to be coming out the exhaust, or at least making its way there quickly.

- Squirted a bit into the chamber, replaced the plug, but still no start.

- Tried with Air filter on and off, no change. Filter seems good.

It doesn't appear to have a head gasket, but from what I've read here, these Vespa's don't have a gasket. I've cleaned the head and it's nice and tight.

I'm out of ideas at this point. Would love some advice. Might be ready to find someone in the neighborhood (Georgetown, Seattle) who might be a bit smarter about this than I.

Re: Vespa Grande not starting. dripping fuel.

diggum seattle /

the guys at the local Vespa (scooter, not moped) shop suggested it was the seals, but i don't know then why I'd be feeling air coming from the front, around the head. more troubleshooting is necessary, i think.

Re: Vespa Grande not starting. dripping fuel.

The fan blows air toward the front so that might be what you are feeling. Check your point gap and your rear light bulb. Make sure no wires got disconnected like at the brake switch or around the engine.

Re: Vespa Grande not starting. dripping fuel.

You are sure there is blue spark from the plug you are using? I guess your float level valve could be stuck open and gas is pouring into the carb body by gravity. If that were the case you would need a tornado directly passing through the Venturi to compensate, that's my guess.

Re: Vespa Grande not starting. dripping fuel.

diggum seattle /

Wanted to respond as I finally fixed it today. Took the carb off and the jet was almost completely unscrewed. I wasn't sure how tight it was supposed to be so I loosely tightened it and it worked for a bit, then got REALY sluggish. eventually, it wouldn't run again. Took the float bowl off once more and the jet had come out altogether.

After tightening it good and tight, i took it out for a 15 mile trip with no problems. Looking good so far. Thanks for all the help.

Re: Vespa Grande not starting. dripping fuel.

Easy fix.. way to go!

Re: Vespa Grande not starting. dripping fuel.

Sounds like could be your float. Take it off and shake it see if is full of fuel

Re: Vespa Grande not starting. dripping fuel.

Word. Check the needle for signs of wear and the needle seat for debri while you're at it.

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