Holley Tuning Part 4
Proper float adjustment will be confirmed when the fuel level is slightly below the site plug hole (as pictured in picture #5 on the previous page), and gently rocking the car side to side allows the fuel to barely spill out of the site plug hole.
Once the proper float level has been set, tighten the set screw (as seen in picture #6 below) making sure the adjuster nut does not move in the process.
*DO NOT OVER-TIGHTEN THE SET SCREW. DOING SO CAN DAMAGE THE THREADS IN THE FLOAT BOWL/ DO NOT TRY TO “TWEAK” THE SETTING BY TURNING THE ADJUSTER NUT WITHOUT LOOSENING THE SET SCREW FIRST. DOING SO WILL RESULT IN DAMAGE TO THE FLOAT BOWL AND POSSIBLE FUEL LEAKS AND A POTENTIAL FOR FIRE.*
Perform this procedure on the front float bowl first, then repeat the procedure on the rear float bowl. Be sure to re-install both the float bowl sight plugs with their respective gaskets once the float levels have been set.
A carburetor’s biggest enemy is dirt! A clean supply of fuel is a must for proper performance. 99% of the carburetors returned to me with complaints have fallen victim to a dirty fuel supply.
Most OEM carburetors will have a sintered bronze filter element installed in the float bowl behind each inlet fitting. *DO NOT REMOVE THESE!* Contrary to popular myth, they do not pose any significant flow restriction provided they are kept clean. If you suspect they are in need of replacement, do NOT simply remove and discard them, be sure to install new replacements.
A clean air filter element is equally important. Some of the passages on a carburetor that are exposed to the air inlet system are as small as .020” (that’s twenty thousands of an inch). It doesn’t take much dirt to plug one up.
These are basic adjustments you WILL be required to perform once you have your carburetor installed. They will be “base lined” when you receive the carburetor, but every application is slightly different and will require further refinement to suit your particular vehicle. If you have any questions or concerns, please don’t hesitate to contact me.
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