20579 Mercury SPRING, CHOKE SHUTTER TO LEVER

1. Remove tube (1). Cap and plug all openings immediately.2. Remove the two bolts that hold fuel ratio control to the governor. Disconnect the fuel ratio control from the lever in the governor, and remove fuel ratio control (2).3. Remove the O-ring seal from the fuel ratio control. Remove the O-ring seals from the rear governor housing. The following steps are for installation of the fuel ratio control.4. Put the O-ring seals in position on the rear governor housing. Put the O-ring seal in position in the fuel ratio control. Put clean engine oil on the O-ring seals.5. Put fuel ratio control in position on the governor. Make sure the flange on the end of the fuel ratio control is behind the groove (slot) in the lever.6. Install the two bolts that hold the fuel ratio control to the governor. One of the two bolts that hold the fuel ratio control to the governor is a tamper resistant bolt and should be tightened until the head shears off, approximately 12 3 N m (9 2 lb ft).7. Install tube (1). For more detailed information regarding the fuel ratio control, see the topic "Fuel Ratio Control" in the Specifications Manual. See the topic "Fuel Ratio Control" in the Systems Operation Testing & Adjusting Manual for the adjustment of the fuel ratio control.Disassemble Fuel Ratio Control
Start By:a. remove fuel ratio control
These emissions regulated engines are equipped with tamper resistant bolts on the fuel ratio control and cover. Adjustments and repairs should be made by an authorized Caterpillar dealer.
1. Remove O-ring seal (1) from the fuel ratio control. 2. Put Tooling (A) in a vise as shown so that the station being used is not over the vise jaw. Place the fuel ratio control over the pins in Tooling (A). Remove cover (2) and the gasket from fuel ratio control.
There is a spring force behind cover (3). Hold cover (3) in position, and slowly remove the bolts that hold it to release the spring force.
3. Remove cover (3) from housing (4). 4. Remove O-ring seals (5) and (6) from the governor housing. 5. Remove spring (9), washer (7), and diaphragm (10) from retainer (8). Remove retainer (8) from housing (11). 6. Remove nut (16) from extension (15), and remove the extension from retainer (8). Remove valve (12), spring (13) and O-ring seal (14) from the extension. 7. Remove spring (18), retainer (17) and spring (19) from the housing. 8. Remove piston assembly (20) from the housing. 9. Use Tooling (B), and remove snap ring (21) and the wave washers from valve assembly (22). Remove piston assembly (23) from the valve assembly.10. Remove seal (24) from piston (23). 11. If necessary, remove stem (26) from valve (25).12. Clean and inspect all parts. Make a replacement of all parts that are worn or damaged.Assemble Fuel Ratio Control
These emissions regulated engines are equipped with tamper resistant bolts on the fuel ratio control and cover. Adjustments and repairs should be made by an authorized Caterpillar dealer.
1. Assemble stem (2) to valve (1) using 9S-3265 Retaining Compound. 2. Put seal (4) on piston (3), and put piston (3) on valve assembly (5). 3. Put two wave washers in position on valve (5), and use Tooling (A) to install the snap ring on the valve assembly. 4. Place housing (7) on Tooling (B), and put Tooling (C) into the bore of the housing. Lubricate Tooling (C) with clean engine oil.5. Put a small amount of clean oil on the seal of the piston assembly, and push piston assembly (6) into position with a smooth swift motion. 6. Place spring (8) and retainer and spring (9) in position in housing (7). 7. Put O-ring seal (12) on extension (13). Put spring (11) and valve (10) in position on the extension.8. Lubricate O-ring seal (12) with clean engine oil. Install extension (13) in retainer (14). Install nut (15). 9. Put diaphragm (18), washer (17) and spring (16) in position on retainer (14). Install retainer (14) in housing (7). 10. Install O-ring seals (19) and (20) on the governor housing. 11. Hold retainer (14) in position, and install cover (21) on the housing. Install the bolts that hold the cover. Tighten the bolts that hold the cover to a torque of 9 3 N m (7 2 lb ft). 12. Make a replacement of the gasket for cover (22), and install the cover. Install the bolts that hold the cover. One of the two bolts that hold the cover on the fuel ratio control is a tamper resistant bolt and should be tightened until the head shears off, approximately 12 3 N m (9 2 lb ft). 13. Put O-ring seal (23) in position on the fuel ratio control. For more detailed information regarding the fuel ratio control, see the topic "Fuel Ratio Control" in the Specifications Manual. See the topic "Fuel Ratio Control" in the Systems Operation Testing & Adjusting Manual for the adjustment of the fuel ratio control.End By:a. install fuel ratio control