Half throttle to keep it going

The original 2-stroke Genuine scooter and its 4-stroke manual and automatic offspring

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Delrey
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Half throttle to keep it going

Post by Delrey »

Hello everybody,

I just got a Stella (2005 with only 200 miles on it). I have been riding different kinds of vespas my entire life, one Bajaj also, I am not a mechanic though.
My problem: the motor seems to be running smoothly, the carb is clean, the noise is what is supposed to be, it starts without a problem but in order to keep the engine going I have to keep at a very high throttle. If I release the throttle it will stop right the way. The idle screw won't change the situation at all.
I have looked at many posts here and on other forums. I am pretty sure the carb is fine, and it shouldn't be an air leak. The spark plug is new and the cable is firmly seated. I disconnected the kill switch and that is not the problem.
Please help!

Ciao

Michele
Last edited by Delrey on Fri Apr 16, 2010 6:55 pm, edited 1 time in total.
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lmyers
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Post by lmyers »

You probably need to adjust the idle up just a bit.
Delrey
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Post by Delrey »

Yes I forgot to mention that, the idle screw doesn't change anything for me... :(
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Silver Streak
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Post by Silver Streak »

You say the carb is clean, but it sounds to me like the idle circuit in the carb has a clog somewhere.
Dave

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"You do not need a parachute to skydive. You only need a parachute to skydive twice."
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jmkjr72
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Post by jmkjr72 »

i would have to agree that it is in the carb
either the idle circut or a massive vacume leak
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Silver Streak
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Post by Silver Streak »

jmkjr72 wrote:i would have to agree that it is in the carb
either the idle circut or a massive vacume leak
+1. The vacuum leak is a good possibility too. Good call.
Dave

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"You do not need a parachute to skydive. You only need a parachute to skydive twice."
Delrey
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Post by Delrey »

sorry for the ignorance: how do I fix a vacuum leak?
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jmkjr72
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Post by jmkjr72 »

a vacume leak is lletting more are into the intake system some where along the way

you find it and replace the gasket or hose that is bad
normaly it is a bad gasket on the carb or intake
you can try rebuilding the carb with all new gaskets and replacing the intake gasket
if you have taken the carb off you could even have the carb warped and not bolted down properly

if you can get it to hold any sort of idle it will be hard to tell but
get it running at the lowest steadiest rpm possible and spary some starting fluid around the intake area(trying not to get it down the throat of the carb) and listen for the rpms to increase or watch a tack if you have one
z 2008 zuma 50
olive 2008 setlla
1979 tomos
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Silver Streak
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Location: Annapolis, MD

Post by Silver Streak »

jmkjr72 wrote:a vacume leak is lletting more are into the intake system some where along the way

you find it and replace the gasket or hose that is bad
normaly it is a bad gasket on the carb or intake
you can try rebuilding the carb with all new gaskets and replacing the intake gasket
if you have taken the carb off you could even have the carb warped and not bolted down properly

if you can get it to hold any sort of idle it will be hard to tell but
get it running at the lowest steadiest rpm possible and spary some starting fluid around the intake area(trying not to get it down the throat of the carb) and listen for the rpms to increase or watch a tack if you have one
On a 2-stroke, it can be bad crankcase seals as well.
Dave

www.glyphukulele.com

"You do not need a parachute to skydive. You only need a parachute to skydive twice."
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