Carburetor Questions Ref. My J175EXEUC

[4TISQ]

As I understand the carburetor design there are two air jet orifices and one fuel jet orifice, the later for WOT operation. The one air jet is a fixed .040" orifice I believe to be for mid-range operation and the other air orifice is a needle valve for idle speed control. I know that with fuel a larger orifice allows more fuel flow, but does a larger air orifice increase or decrease the fuel?? Is there any other reason this motor will only run if I activate the solenoid primer?? There is fresh fuel in all 6 bowls.

 

[Chris1956]

If your motor will not idle without activating the solenoid primer, I would suspect dirt in the idle circuit.

 

[boobie]

Or dirt in the high speed jet which feeds the other circuits.

 

[4TISQ]

Thanks for the info, I now have a better understanding of how these carbs are supposed to work.

 

[gm280]

You could also have a fuel pump problem where the pump isn't dead, but not pumping the correct volume or pressure... Worth a check anyways... JMHO!