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
