Disassembly

Fig. 2 Typical exploded view of Holley model 6520 carburetor:

1. Remove fuel inlet fitting from air horn.
2. Disconnect and remove choke operating rod and choke rod seal.
3. Remove duty cycle or oxygen feedback solenoid retaining screw and carefully lift solenoid from airhorn, Fig. 2.
4. Remove idle stop solenoid anti-rattle spring, then the solenoid retaining screws and idle stop solenoid, if equipped.
5. Remove wide open throttle cutout switch mounting screws, marking location for proper installation, if applicable.
6. Remove harness mounting screws and open retaining clip, then remove wires from connector and thread through clip.
7. Remove air horn mounting screws and separate air horn from main body.
8. Remove float level pin, float and float inlet needle.
9. Remove fuel inlet seat and gasket.
10. Remove secondary main metering jet, noting its size so that it can be installed in proper location.
11. Remove primary main metering jet, noting its size so that it can be installed in proper location.
12. Remove secondary high speed bleed and main well tube, noting their sizes so that they can be installed in proper locations.
13. Remove primary high speed bleed and main well tube, noting their sizes so that they can be installed in proper locations.
14. Remove discharge nozzle screw, discharge nozzle and gasket.
15. Invert carburetor and drop out accelerator pump discharge weight ball and check ball.
16. Remove accelerator pump cover attaching screws, then the cover, accelerator pump diaphragm and spring.
17. Remove choke diaphragm cover screws, then the cover and spring.
18. Rotate choke shaft and lever assembly counterclockwise, then rotate choke diaphragm assembly clockwise and remove assembly from housing.
19. Remove mixture adjusting screw concealment plug, then the idle mixture screw.