Engine Tuning with Vacuum Gauge

1. Check plugs.

• Old need to be replaced. Fuel fouled can be cleaned and re-gaped.
• Gap on a Electronic ignition (Duraspark, Davis HEI, Pertronix) should be around .35 to .45 (check with your distributor manufacturer). Points type ignition should have the plugs gaped to around .16 (check the service manual for correct gap).

Run engine. Check for your miss. If it is gone you have found your miss.

2. Check float level. Generally examine carburetor. Look for unplugged vacuum ports, things like our accelerator pump where it is not even hooked up.
• Carb basics. Idle screw.
• Idle jets
• accelerator pump
• float setting on Holley

Run engine.

3. Vacuum check with Carb cleaner around carburetor base and intake.
• Older carbs check throttle shafts. You are looking for an increase in vacuum.

4. Timing. This can be tuned with a vacuum gauge or a timing light. This engine is an unknown, and is somewhat cobbled together. So we are going to use a vacuum gauge.

Run engine.

5. Tune carburetor for best performance. Use vacuum gauge to make sure you have the engine running at it’s best.