Please note: there are many things that could cause your vehicle to have poor fuel economy, we are only discussing possible problems with the carburetor in this article.

Most common cause:

• power pistion sticking in bore

• float level incorrect

  

• check needle and seat for leaks - instructions for testing it here

• check nitrophyl float for proper weight, or brass float for leaks

Other possibilites:

• air bleed port(s) clogged
• loose main passage plugs, or loose primary or secondary main jet
• power valve defective
• power piston bore surface scored
• power jet missing
• air horn gasket torn or leaking
• air horn warped
• air horn to main body mounting screws loose
• power piston vacuum passage clogged
• choke valve not adjusted properly
• reloader not operating or improperly adjusted
• flange gasket covers vacuum source passage