Idle Mixture Check & Adjust (Propane Enrichment)

With engine at normal operating temperature, choke fully open and A/C "OFF" (if equipped), set parking brake and block drive wheels. Disconnect and plug hoses as directed on Emission Control/ Tune-Up decal.
Connect tachometer to engine. Disconnect vacuum advance and set timing to specification. Reconnect vacuum advance. Disconnect crankcase ventilation tube from air cleaner.
Insert hose with rubber stopper (tool J-26911) from propane valve into PCV tube opening in air cleaner. Propane bottle must be in vertical position.
Slowly open control valve until maximum engine speed is reached with transmission in "D" (automatic) or neutral (manual).
NOTE: Too much propane will cause engine speed to drop.
Observe propane flow meter to ensure propane cartridge is full. With propane flowing, adjust idle speed screw or solenoid so speed rises above normal idle by specified amount.
Readjust propane flow to be certain of maximum engine speed and adjust idle speed if necessary. Turn off propane. Run engine at 2000 RPM in neutral for 30 seconds, return to idle, and place in "D".
Check idle speed. If correct, no adjustment of mixture is necessary. If not correct, proceed with adjustment procedure. If idle speed is too low, carefully remove caps from mixture screws and back out screws (richen) 1/8 turn at a time until correct speed is reached.
If RPM is too high, turn screws in (leaner) 1/8 turn at a time until correct speed is reached. Turn propane on again to check maximum engine idle speed.
If RPM does not meet specifications, readjust idle speed screw or solenoid screw to obtain specified enriched RPM with propane flowing.
Turn off propane, place transmission in neutral and run engine at 3000 RPM for 30 seconds. Recheck idle speed and repeat procedure if necessary.

PROPANE ENRICHED RPM

Application	Manual Trans.	Auto. Trans.
5.7L 4-Bbl
Federal	100	40
Federal High Altitude	100	20