Memphis Kings Scooter Club

Jag · 2nd Lt. Joined: 04 Oct 2008 Posts: 1

Hi guys,

Am writing to you from Africa and was wondering if you could be of assistance.

I have a Piaggio Sfera 50 and recently it has broken down. Unfortunately there is no one here who can fix it. I will try to describe the problem. The scooter starts and runs for about 10 seconds and then stalls. I took out the fuel line from the fuel tap and i noticed that when i accelerate the fuel tap stop supplying fuel. This tap had two pipes coming out of it both from the carb. One pipe pushes air into the tap and the other pushes fuel out of the tap. Without turning the accelerator the tap works fine but when i accelerate no fuel is pushed out. Now i think the problem is with the carb but am not sure what to do. Does anybody out there know?

BSSart · Posted: Sat Oct 04, 2008 11:32 am Post subject:

I cross posted this and will check for replies. I am not good with fuel delivery stuff.

Cheers,
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- - Ride a scooter. Be a hero.

troublemaker · Captain Joined: 11 May 2008 Posts: 23 Location: Cordova

Without being able to see it, it will be difficult to diagnose, but this might help you.

The two tubes that go from the tap to the carb are indeed air and fuel, but the one that has air is for vacuum, not pressure. It works like this: The fuel tap has a spring loaded valve for shutting off the fuel. Below the valve, there is a vacuum diaphragm. Vacuum pulls the diaphragm when the engine is running, which opens the fuel valve and lets fuel pass through the line and into the carburetor. When the engine is shut off, the spring closes the valve again. Also, fuel is never "pushed" out of the tap. It is gravity-fed. When the valve is open, fuel should run through on it's own.
You either have a bad fuel tap, or lack of vacuum in the engine. If your engine compression is good, I would look for a vacuum leak. Make sure there are no large holes in the air filter element, which can cause lower than normal vacuum.

I have never worked on the Sfera 50, but I would be willing to bet that it is the exact same fuel tap they put in the ET2, ET4, and GT200. And lately have seen several of them go bad. However, the problem is not lack of fuel. These taps have stayed open and allowed fuel to run into the carb and fill up the crank case and muffler....and make puddles.

When you pinpoint the problem, please post and let us know what it was.
_________________
Jason Mitchell
TroubleMaker Customs
www.troublemakercustoms.com

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