Since the design of the 2700VV and 7200VV carburetor is different from all other Motorcraft carburetors in many respects, the adjusting procedures are necessarily different as well. Although the idle speed adjustment alone is identical, there is further information you will need to know in order to adjust the 2700VV and 7200VV properly. Refer to Emission Controls for an explanation.
See Figures 1, 2, 3 and 4
- Start the engine and run it at idle until it reaches normal operating temperature (about 10-15 minutes, depending on outside temperature). Stop the engine.
- Check the ignition timing as outlined earlier in this section.
- Remove the air cleaner, taking note of the hose locations, and check that the choke plate is fully open (in a vertical position). Check the accompanying illustrations or those in Fuel System to see where the carburetor adjustment locations are. If you cannot reach them with the air cleaner installed, leave it off temporarily. Otherwise, reinstall the air cleaner assembly including all of the hose connections.
Leaving the air cleaner removed will affect the idle speed. Therefore, adjust the curb idle speed to a setting 50-100 rpm higher than specified, if the air cleaner is off. When the air cleaner is reinstalled, the idle speed should return to specifications.
- Attach a tachometer to the engine, with the positive wire connected to the distributor side of the ignition coil, and the negative wire connected to a good ground, such as an engine mount. The ignition coil connector allows a tachometer test lead with an alligator clip to be connected to the DEC (Distributor Electronic Control) terminal without removing the connector.
- All idle speed adjustments are made with the headlights off (unless otherwise specified on the engine decal), with the air conditioning off (if so equipped), with all vacuum hoses connected, with the throttle solenoid positioner activated (connected, if so equipped), and with the air cleaner on. (See Note after Step 3.) Finally, all idle speed adjustments are made in Neutral on cars with a manual transmission, and in Drive on cars equipped with an automatic transmission.
- On cars not equipped with a Throttle Solenoid Positioner (TSP), the idle speed is adjusted with the curb idle speed adjusting screw. Start the engine. Turn the curb idle speed adjusting screw inward or outward until the correct idle speed (see Tune-Up Specifications chart) is reached, remembering to make the 50-100 rpm allowance if the air cleaner is removed.
- On cars equipped with a TSP, idle speed is adjusted by a solenoid adjusting screw (nut), in two stages. Start the engine. The higher speed is adjusted with the solenoid connected. Turn the solenoid adjusting screw (nut) on 1 or 4-barrel carburetors, or the entire bracket on 2-barrel carburetors inward or outward until the correct higher idle speed (see Tune-Up Specifications chart) is reached, remembering to make the 50-100 rpm allowance if the air cleaner is removed. After making this adjustment on cars equipped with 2-barrel carburetors, tighten the solenoid adjusting locknut. The lower idle speed is adjusted with the solenoid lead wire disconnected near the harness (not at the carburetor). Place automatic transmission equipped cars in Neutral for this adjustment. Using the curb idle speed adjusting screw on the carburetor, turn the idle speed adjusting screw inward or outward until the correct lower idle speed (see Tune-Up Specifications chart) is reached, remembering again to make the 50-100 rpm allowance if the air cleaner is removed. Finally, reconnect the solenoid, slightly depress the throttle lever and allow the solenoid plunger to fully extend.
- If removed, install the air cleaner. Recheck the idle speed. If it is not correct, Step 6 will have to be repeated and the appropriate corrections made.
- To adjust the idle mixture, turn the idle mixture screw(s) inward to obtain the smoothest idle possible within the range of the limiter(s).
- Turn the engine OFF , then disconnect the tachometer.
If any doubt exists as to the proper idle mixture setting for your car, have the exhaust emission level checked at a diagnostic center or garage with an exhaust (HC/CO) analyzer or an air/fuel ratio meter.