Förgasar-renovering och -justering Rochester 4 MV, M4MC, M4MC, M4MEA

1. Carefully read the text in the following pages to become familiar with the contents of this worksheet before performing carburetor overhaul.
2. The exploded view shown is typical of the model carburetor this kit will service. The view may differ slightly from the actual carburetor being overhauled.
3. Use the exploded view as a guide. The numerical sequence may generally be followed to disassemble the carburetor far enough to permit cleaning and inspection.
4. Parts list shown DOES NOT reflect the contents of the kit.
5. Kit may contain extra parts intended for other carburetors within this group. Sustitute identical replacement parts for original worn parts found in carburetor.
CLEANING
Cleaning must be done with carburetor disassembled. Use spray cleaner and a stiff bristle brush to remove dirt and carbon deposits. Do not use abrasives and wires to clean parts and passageways. Wash off in suitable solvent, and clear all passageways with compressed air. Caution: When cleaning with solvent do not soak or spray parts containing rubber, leather, plastic and electrical components.

DISASSEMBLY and ASSEMBLY NOTES
• Air horn screws (17) are located inside air horn assembly (18). • Install seal 40A with lip facing in and seal 40B with lip facing out.
• Pump lever pin (9) can be driven in to release pump lever (10). • Do not assemble choke cover assy. (35) until choke rod adjustment is made.
• On models with main (25) and auxiliary power pistons (not shown) make sure • On models with electrical choke, do not install gasket (36). to mark their respective springs upon disassembly. They are not interchangeable.
• Primary jets (28) are the only jets removable.
• Before removing idle adjusting needles (55), turn each needle in. Count and record number of turns until lightly seated. Use data for proper reassembly.
• 1976 models have A.P.T. adjustment screw. Refer to Fig. 2.
• Reassemble in reverse order of disassembly.
• Assemble new pump piston (found in kit) with spring and retainer saved from old pump piston assy.
• Tighten fuel inlet fitting (48) securely (18 ft./lbs.). Do not over-tighten.
• Tighten air horn screws in sequence shown in exploded view.
• Refer to Fig. 2A for flange gasket style.

FIG. 1 REMOVAL OF SEALED MIXTURE SCREWS (IF REQUIRED) 1. INVERT THROTTLE BODY AS SHOWN. 2. PLACE PUNCH BETWEEN 2 LOCATION MARKS OVER IDLE MIXTURE NEEDLE PLUG. 3. BREAK OUT THROTTLE BODY TO PROVIDE AC CESS TO HARDENED STEEL PLUG. NEXT, DRIVE OUT PLUG EXPOSING MIXTURE NEEDLE. NOTE: BEFORE REMOVING MIXTURE NEEDLE, CAREFUL LY MARK POSITION. THEN, USING A SOCKET WRENCH, TURN NEEDLE IN COUNTING NUMBER OF TURNS TO LIGHTLY SEAT. NEXT, TURN OUT COUNTING NUMBER OF TURNS TO ORIGINAL INDEX MARK. RECORD SETTING & REMOVE NEEDLE. REPEAT PROCEDURE FOR OTHER MIXTURE NEEDLE. 4. LATE MODELS: CUT 2 PARALLEL SLOTS ON EITHER SIDE OF LOCATION MARKS USING A HACKSAW. SLOTS SHOULD NOT EXTEND BEYOND 1/8 OF LOCATION POINTS. 5. POSITION A FLAT PUNCH AT A 45° ANGLE BETWEEN ENDS OF SAW MARKS IN THROTTLE BQDY. DRIVE PUNCH BETWEEN SLOTS CAUSING SLUG TO BREAK OFF. 6. NEXT, HOLD CENTER PUNCH IN A VERTICAL POSITION & DRIVE IT INTO STEEL PLUG. REPOSITION PUNCH TO A 45° ANGLE & DRIVE PLUG OUT OF CASTING EXPOSING MIXTURE NEEDLE. 7. REPEAT NOTE OF STEP 3 TO INDEX MIXTURE NEEDLES.
FIG. 2 METERING ROD ADJ. SCREW - LOCATION 1. CAUTION: DO NOT REMOVE OR ALTER THE A.P.T. (ADJUSTING PART THROTTLE) METERING ROD ADJUSTING SCREW. THIS SCREW SETS THE MAXIMUM DEPTH OF METERING ROD TRAVEL WITHIN THE MAIN JET ORIFICE. OTHER MODELS: THIS ADJUSTMENT MAY BE LOCATED ON TOP OF A BELLOWS ASSEMBLY (NOT SHOWN). THESE UNITS ARE FACTORY PRESET. IT IS NOT ADVISABLE TO ALTER ANY SETTING IN THE FIELD.
FIG. A FLOAT LEVEL ADJUSTMENT 1. HOLD FLOAT RETAINER FIRMLY IN PLACE. 2. PUSH FLOAT DOWN LIGHTL AGAINST NEEDLE DO NOT PRESS NEEDLE INTO SEAT. 3. MEASURE FROM TOP OF FLOAT TO TOP OF CASTING. NOTE: MEASURING POINT IS 3/16" BACK FROM TOE OF FLOAT 4. TO ADJUST, BEND FLOAT ARM. NOTE: See fig. J for proper float needle and clip location.
FIG. B ACCELERATOR PUMP ADJUSTMENT AND ROD LOCATION NOTE: COMPLETELY CLOSE THROTTLE VALVES. 1. POSITION PUMP ROD IN SPECIFIED HOLE OF PUMP LEVER. 2. MEASURE DISTANCE BETWEEN TOP OF CHOKE VALVE WALL AND TOP OF PUMP STEM. 3. TO ADJUST, BEND PUMP LEVER.
FIG. C CHOKE ROD ADJUSTMENT NOTE: PLACE DEGREE SCALE ON CLOSED CHOKE VALVE AND CENTER LEVELING BUBBLE ON GAUGE. 1. MOVE DEGREE SCALE ONLY TO SPECIFIED ANGLE. 2. PLACE CAM FOLLOWER ON RECORD STEP OF CAM (NEXT TO HIGH STEP). 3. CLOSE CHOKE BY PUSHING UPWARD ON CHOKE COIL LEVER. 4. TO ADJUST, BEND TANG ON FAST IDLE CAM UNTIL BUBBLE IS CENTERED.
FIG. D AIR VALVE ROD ADJUSTMENT NOTE: COMPLETELY CLOSE SECONDARY AIR VALVE. 1. SEAT DIAPHRAGM BY APPLYING AN OUTSIDE VACUUM SOURCE. 2. MEASURE BETWEEN ROD AND END OF SLOT IN LEVER. 3. TO ADJUST, BEND ROD.
FIG. E AIR VALVE SPRING WIND-UP ADJUSTMENT NOTE: COMPLETELY CLOSE SECONDARY AIR VALVE. 1. LOOSEN LOCK SCREW. 2. TURN ADJUSTING SCREW SPECIFIED NUMBER OF TURNS AFTER SPRING CONTACTS PIN. 3. TIGHTEN LOCK SCREW.
FIG. F FRONT VACUUM BREAK ADJUSTMENT NOTE: PLACE DEGREE SCALE ON CLOSED CHOKE VALVE AND CENTER LEVELING BUBBLE ON GAUGE. 1. MOVE DEGREE SCALE ONLY TO SPECIFIED ANGLE. 2. SEAT DIAPHRAGM BY APPLYING AN OUTSIDE VACUUM SOURCE. NOTE: ON DELAY MODELS, COVER AIR BLEED HOLE WITH A PIECE OF TAPE. REMOVE TAPE AFTER ADJUSTMENT. 3. TURN CHOKE VALVE TOWARD CLOSED POSITION BY ROTATING CHOKE COIL LEVER COUNTERCLOCKWISE. 4. TO ADJUST, TURN SCREW UNTIL BUBBLE IS CENTERED.
FIG. G REAR VACUUM BREAK ADJUSTMENT NOTE: PLACE DEGREE SCALE ON CLOSED CHOKE VALVE AND CENTER LEVELING BUBBLE ON GAUGE. 1. MOVE DEGREE SCALE ONLY TO SPECIFIED ANGLE. 2. SEAT REAR DIAPHRAGM BY APPLYING AN OUTSIDE VACUUM SOURCE. NOTE: ON DELAY MODELS, COVER AIR BLEED HOLE WITH A PIECE OF TAPE. REMOVE TAPE AFTER ADJUSTMENT. 3. TURN CHOKE VALVE TOWARD CLOSED POSITION BY ROTATING CHOKE COIL LEVER COUNTERCLOCKWISE. 4. TO ADJUST, BEND LINK UNTIL BUBBLE IS CENTERED.
FIG. H UNLOADER NOTE: PLACE DEGREE SCALE ON CLOSED CHOKE VALVE AND CENTER LEVELING BUBBLE ON GAUGE. 1. MOVE DEGREE SCALE ONLY TO SPECIFIED ANGLE. 2. PUSH UP OR DOWN ON LEVER TOWARDS CLOSED CHOKE. NOTE: HOLD PRIMARY THROTTLE VALVES WIDE OPEN. 3. TO ADJUST, BEND TANG UNTIL BUBBLE IS CENTERED.
FIG. I AUTOMATIC CHOKE ADJUSTMENT NOTE: POSITION FAST IDLE SCREW ON HIGH STEP OF FAST IDLE CAM. 1. LOOSEN 3 HOLD-DOWN SCREWS. NOTE: SOME MODELS HAVE CHOKES WHICH DO NOT REQUIRE ADJUSTMENT. HOWEVER, IF DISASSEMBLY BECOMES NECESSARY, SCRIBE A REFERENCE LINE FROM CHOKE COVER TO HOUSING THEN DRILL OUT RIVETS USING A NO. 21 DRILL (.159"). REASSEMBLE TO REFERENCE MARK USING SIMILAR RIVETS OR APPROPRIATE SIZE SHEET METAL OR SELFTAPPING SCREWS. 2. POSITION SCRIBE LINE'ON ELECTRIC CHOKE TO SPECIFIED MARK ON CHOKE HOUSING. CHOKE VALVE MUST BE SPRING-LOADED TOWARD CLOSED POSITION.
	FIG. 2A NEW STYLE FLANGE GASKET SUPPLIED WITH KIT MAY BE DIFFERENT THAN THE OLD STYLE FLANGE GAKSKET. THIS GASKET MATCHES THE CURRENT O.E. DESIGN AND IS FULLY FUNCTIONAL.

*number of turns