2F Carburetor Adjustment and Tuning Guide

This page provides an overview of the areas for adjustment or tuning for the 2F carburetor. Please consult the factory service manual (FSM) for official information and detailed steps.

1. Idle mixture - Adjustment is mandatory. Initial adjustment is to screw in the idle mixture screw all the way in and then back out 1 1/2 turn. Take care not to screw in too tightly and damage the screw tip.
2. Float adjustment - Not mandatory but occasionally needed if not obtaining proper fuel level half way up the sight glass. Note: Debris getting into the needle and seat can also affect the fuel level.
3. Jets - The ideal jet size is location dependent
1. We believe the carb comes with 136 primary jet. Some US customers have reported that the car runs stronger with 147-150 primary jet.
2. If you live at 4000+ feet above sea level, you should consider switching to high altitude jets.
3. The easiest time to change jets is before installing the carb. Some shops are able to drill into the existing jets to enlarge it, or you can buy new ones from a site like Jets R Us (no affiliation).
4. It's not necessary to change the secondary jet.
4. Fast idle adjustment is optional. Refer to the FSM for procedure if needed.
5. Ported vacuum from the carb should be 0 hg at idle. If it's significantly above 0, you would need to adjust the throttle positioner and secondary kickup settings. This is uncommon.
6. Always install a new fuel filter with a new carb.