- Engine:
- 3508B (S/N: 1FZ1-UP; S2B1-UP; S2D1-UP; S2E1-UP; S2F1-UP; BAG1-UP; 2BM1-UP; 7SM1-UP; 1TW1-UP; 2HW1-UP; 3DW1-UP; BPX1-UP; CBB1-UP; 6PN1-UP; S2A1-UP; LPD1-UP; 3DM1-UP; 5PS1-UP; CTC1-UP)
- Generator Sets:
- 3508B (S/N: CNB1-UP)
- Pumper:
- SPF343 (S/N: 6RZ1-UP)
- 3508 (S/N: 8TL1-UP)
- 3512B (S/N: S2J1-UP; S2K1-UP; S2L1-UP; S2M1-UP; 7HM1-UP; 8EM1-UP; BRN1-UP; 4TN1-UP; 1PW1-UP; 2GW1-UP; 4AW1-UP; 5AW1-UP; 2EZ1-UP; CTB1-UP; CTH1-UP; BRC1-UP; 2AF1-UP; 4DR1-UP; 3ZW1-UP; NSC1-UP; FFG1-UP)
- 3516B (S/N: CBN1-UP; 8CN1-UP; 8KN1-UP; 9AN1-UP; S2R1-UP; 2FW1-UP; 3CW1-UP; 4BW1-UP; S2X1-UP; CTA1-UP; 1NW1-UP; CTJ1-UP)
- 3516B (S/N: LEK1-UP)
- SPT343 (S/N: 5XZ1-UP)
ReferenceSpecial Instruction, REHS2814
ReferenceSpecial Instruction, REHS3005
 | |
| Illustration 1 | g01294710 |
Typical examples of air shutoff valves (1) Butterfly / throttle blade style (2) Swing gate style (3) New switch location (4) 289-8498 Damper | |
 | |
| Illustration 2 | g01201688 |
Old switch location (typical example) | |
The new air shutoff valves are for all 3500B and 3500C Engines that are equipped with two, swing gate type air shutoff valves. This change does not affect engines with the following equipment.
- Two butterfly valve (1) air shutoff valves
- Single air shutoff valve
For engines that are equipped with two butterfly valve (1) air shutoff valves, contact the dealer in order to upgrade to the swing gate (2) air shutoff valve.
Improved air shutoff valves that include the updated switch assembly are available. The improved assemblies also include a vibration damper (4). The purpose of the vibration damper is to reduce the vibration of the gate. The gate has also been chamfered in order to minimize the wear of the housing. The vibration damper is applicable to engines that are equipped with the new part numbers that are listed below. Refer to Table 2.
Refer to Special Instruction, REHS2814 for information. This Special Instruction provides information on upgrading the valves.
| Part Numbers for the Air Shutoff Valves | |
| Former Air Shutoff Gp | New Air Shutoff Gp |
| 225-7836 (1) 272-7092 |
288-2756 |
| 225-7837 (1) 272-7093 |
288-2757 |
| 230-6305 (1) 272-7094 |
288-2758 |
| 230-6306 (1) 272-7095 |
288-2759 |
| 230-6307 (1) 272-7096 |
288-2760 |
| 230-6308 (1) 272-7097 |
288-2761 |
| 233-7873 (1) 272-7100 |
289-9117 |
| 233-7874 (1) 272-7101 |
289-9118 |
| 230-6309 (2) 272-7098 |
288-2762 |
| 230-6310 (2) 272-7099 |
288-2763 |
| 288-2764 | |
| 288-2765 | |
| ( 1 ) | Cancelled part number |
| ( 2 ) | This part number has not been cancelled. |
The 289-8498 Damper is serviceable. Refer to Table 2. The new air shutoff valves include the relocated limit switches and the vibration dampers.
 | |
| Illustration 3 | g01294099 |
Typical example (4) 289-8498 Damper | |
 | |
| Illustration 4 | g01294119 |
Typical example | |
| Parts for the 289-8498 Damper | ||
| Item | Part Number | Description |
| 5 | 288-2766 | Housing |
| 6 | 288-2767 | Spring |
| 7 | 288-2768 | Plunger |
| 8 | 3J-1907 | O-Ring Seal |
| 9 | 9S-8004 | Plug |
The air shutoff valves must be tested after every 500 hours of operation. The vibration damper assembly must be serviced after every 6000 hours of operation. Refer to Special Instruction, REHS3005 for the inspection and maintenance instructions for the damper.