W350 1 Ton Pickup 4WD V8-360 5.9L VIN 1 4-bbl (1988)
Propane Supply Tool
6. Disconnect the vacuum supply hose from the choke diaphragm at the carburetor and connect the propane supply hose in its place. Make sure that
all other vacuum connectors remain intact.
7. Apply vacuum to the HIAS door diaphragm, which opens the door.
8.
Make sure that propane supply remains upright during entire procedure.
9. Remove PCV valve from valve cover and allow to draw underhood air.
10. Start engine and allow to run for at least 2 minutes. Open propane main valve.
11. Slowly open propane metering valve until maximum RPM is reached. Too much propane will cause the RPM to drop, fine tune the metering
valve to get maximum RPM.
Idle Speed Screw
12. With propane still flowing, adjust idle speed screw to obtain specified propane RPM. See SPECIFICATIONS for propane enrichment rpm
specifications.
13. Adjust propane metering valve again to obtain maximum RPM. If there has been a change in idle speed RPM, readjust idle speed screw to
propane RPM specifications.
14. Turn off propane valve and allow engine RPM to stabilize.
15. Slowly adjust mixture screws 1/16 of a turn at a time, allowing 30 seconds between adjustments for engine speed to stabilize. Adjust for
smoothest idle at specified curb idle RPM.
16. Turn on main propane valve and adjust metering valve to obtain maximum engine RPM. If maximum engine speed differs by more than 25 RPM
from specified propane RPM, repeat steps 10 through 15.
17. When adjustment is correct, turn off both propane valves, stop engine and remove propane supply.
18. Install PCV valve and all vacuum hoses.
19. Install concealment plugs, then perform "Curb Idle Speed, Adjust" and "Fast Idle Speed, Adjust" procedures.
