Engine won't idle unless choke is out slightly. By oldsurfer73 (Read 620 times)

[oldsurfer73]

I've got an old 1974 Vespa large frame VLB (VIN - VLB1TO174544) 
I put a new carb on it 2 1/2 yrs ago, last week it started running rough and would die at stop light. I ordered new gaskets and pulled carb apart and let it and all parts sit in carb cleaner overnight. Next day put it back together and on the engine. It made no difference, problem persists. Scooterwest guy told me to run a small wire down the idle jet port because there seems to be something plugging the passageway. Did that but still no luck. ? Do you guys have any ideas? My next thought would be a new Carb.  BTW I put in a new spark plug and road around for an hour and pulled the plug to check for carbon. Yup, lots of black carbon on the plug.  Much appreciate any help you guys can give.
Thanks,
Bill

[czmdiver]

When ever we use the choke to keep her running your just Bypassing a clogged Carb Circuit.
How long did it ever set with the New Carb?
Remamber Alchohol/ Ethanol is Corrosive to Aluminium, The Smaller the Carb, the longer she sits the Bigger the Problem.
The Power Equipment Industry(Saws,Blowers, Mowers etc) are selling tons of new carbs as the small Walbro etc carbs once Corroded Internally are Finished, you never get a hot tank or tother to get it out.

[dyoung1167]

my father always boiled dirty carbs in white vinegar. a bit stinky for the house so a grill for this would be helpful. I do not remember if it was in the pot as heated or put in after the boiling started but but i can say, we never once bought a new carb or even rebuild kits and i'm talking 6 very frequently used and abused dirt bikes.

[crwford]

Before I do that I would be looking for a vacuum leak causing it to run lean, and by you adding a little choke you are riching it back to normal.