Modern Vespa

Last fall in Crete, I had my Typhoon 125 2T running well. I left it with a neighbor who was supposed to start it regularly... well, he didn't. Except he tried to start it once (and I don't know how many months it sat before the attempt), ran the new battery way down - and just shrugged and left it.

So I just returned a few days ago as usual... bought a new battery again, added a couple of liters of fresh gas, and cranked... no fire. Not a peep. So he wasn't wrong about that. I removed the seat bucket and took the carb out. It wasn't getting fuel, and only a very little stale gas came out from the drain screw. Then I applied vacuum to the fuel tap, and there was plenty of gas coming out the line to the carb. That pretty much leaves the needle and seat.

I removed the carb and took the bowl off. Very clean inside there, float was free, but the needle seemed to be stuck. I sprayed some carb cleaner into the fuel inlet and worked it several times. Now fuel will come into the bowl and out the drain screw in a vigorous stream. So far so good. All the jet passages are clean and pass the carb cleaner spray, too.

Next I put the carb back on, and it fired up and idled. BUT as soon as I revved it up, it began missing and died just like it ran out of fuel. It will idle indefinitely, and at a steady above-idle rpm. Opening the throttle will rev up - and then die, unless I let off the throttle and wait a few seconds at idle.

Unless I'm way off base, this is telling me that there is barely enough fuel getting through for minimum power (idle). I believe the needle/seat is still gummed up. Should have taken it apart too, but with it open after cleaning I thought I'd get away without it. So much for shortcuts.

Clean the carb / jets and it will probably run fine after that…