carb vent

foreverfaster

Premium User
Stock motor, stock jet 28, new motor from the box, minus carb ( needed elseware)

threw together a carb from parts to help a friend, seems to run fine on the bench but i noticed the fuel line from the pump to the carb is almost empty all the time... if i pull the line from the carb side of the pump, the fuel will flow with out the motor running (hanging fuel line) so i know the pump is got free flow..
Why won't my fuel line stay full on the carb side.. NEW PUMP round walburo. is there a bowl vent issue and where should i look??
 

alvin l nunley

Premium User
A vacuum is created in the carburetor. Air pressure pushes fuel through the fuel line to the carburetor. This in a static system, just sitting there running. Air in the fuel line can come from 2 places. The fuel tank or the carburetor. Sloshing fuel can uncover the pickup point in the tank and air can get pushed into the fuel line. The same thing can happen from the carburetor end of the fuel line. Exactly how that is happening would have to be determined. It could be a loose fitting, or loose fuel line, or some internal problem. I know one thing, you create a vacuum in the carburetor, the atmospheric pressure tries to push into the carburetor to fill a vacuum. The push will find the path of least resistance.
 

foreverfaster

Premium User
fake Walbro pump?? my pump says MEXICO on it.. not that i care, but it doesn't look exactly like any of the walbro pumps that came on my 206's it only looks like 2 sections from the side and the others look like 3 sections. is there a knock off pump... i bought 5 in my last purchase knowing i was going to need them and a couple for spares. ive tried 3 now and non will push the fuel like they should.. any thoughts or opinions??? pulsed off the guvnor rod hole. short hose to the pump.
 
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