The following procedure uses a propane enrichment method of adjusting the idle. Use extreme care when using the propane tank. Make sure that it is in a secure location and that the fittings are not leaking.Holley and Mikuni Carburetors
- Disconnect and plug the EGR hose. Disconnect the oxygen sensor, if equipped.
- Disconnect and plug the hose at the canister.
- Remove the PCV hose from the valve cover and allow it to draw under hood air.
- Ground the carburetor switch with a jumper wire, if equipped.
- Disconnect the vacuum hose from the computer, if equipped and connect an auxiliary vacuum supply of 16 in. Hg (54 kPa).
- Remove the concealment plug. Disconnect the vacuum supply hose to the tee and install a propane supply hose in its place.
- Make sure all accessories are OFF . Install a tachometer and start the engine. Allow the engine to run for 2 minutes to stabilize.
- Open the main propane valve. Slowly open the propane metering valve until the maximum engine rpm is reached. When too much propane is added, the engine will begin to stumble; at this point back off until the engine stabilizes.
- Adjust the idle rpm to obtain the specified propane rpm. Fine tune the metering valve to obtain the highest rpm again. If there has been a change to the maximum rpm, readjust the idle screw to the specified propane rpm.
- Turn the main propane valve off and allow the engine to run for 1 minute to stabilize.
- Adjust the mixture screw to obtain the smoothest idle at the specified idle rpm.
- Open the main propane valve. Fine tune the metering valve to obtain the highest rpm. If the maximum engine speed is more that 25 rpm different than the specified propane rpm, repeat the procedure.
- Turn the propane valves off and remove the propane canister. Reinstall the vacuum supply hose to the tee.
- Perform the idle speed adjustment procedure.
- Connect all wires and hoses that were previously disconnected.