B150 1/2 Ton Van L6-225 3.7L VIN E 1-bbl (1982)
Air/Fuel Mixture: Adjustments
Fig.38 Propane Enrichment Tool
This procedure should only be used after normal diagnosis has revealed no other faults, or if carburetor has been overhauled. Idle mixture adjustment
requires artificial propane enrichment. A propane enrichment tool, C-4464 or equivalent, Fig. 38, must be used to adjust idle mixture. Before
proceeding, make sure that propane cylinder is adequately filled to insure correct propane flow.
Air cleaner must remain in place and A/C control must be in off position, except where noted. Disconnect and plug vacuum hoses at EGR valve and
distributor, and control hose at vapor canister.
Holley Carburetors
1. Remove carburetor from engine and remove throttle body from carburetor.
2. Clamp throttle body in vise with mixture screws facing up. Make sure that vise jaws do not damage gasket surfaces.
3. On 1981 models:
Fig.42 Concealment Plug Removal (Typical)
a. Drill a 5/64 inch pilot hole in casting around each mixture screw, directly above limiter pin, Fig. 42, then enlarge hole to 1/8 inch.
b. Drive out pins with a suitable punch.
4. Drill a 5/64 inch pilot hole on manifold side of casting around each mixture screw, Fig. 42, at a 45° angle toward concealment plug, then enlarge
hole to 1/8 inch.
5. Drive out concealment plugs with a blunt punch.
6. On 1981 models, insert a new limiter pin, allowing clearance for mixture adjustment.
