Manual Lowering of Main Boom

If the engine stops during operation, the main boom may have to be lowered manually by turning the adjustment screw on the main boom valve spool port relief.

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causym CAUTION: Prevent possible injury from unexpected machine movement. Clear all persons and material from the area when lowering the boom with the engine stopped. Make all valve adjustments slowly, and DO NOT remove any components.

1. Locate the main valve and the main boom raise port-relief at the rear of the main boom valve section.


1-Main Valve

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causym CAUTION: Verify that the area is clear and no bystanders are present before lowering the boom. Failure to follow proper safety precautions may lead to risk of personal injury or death.

2. Locate, and mark, the position of the port-relief adjusting screw (A) so that the port relief can be reset after the main boom has been lowered.

3. Loosen, DO NOT REMOVE, the jam nut (B) on the port relief. Exercise care not to turn the port-relief adjusting screw during this step.

4. Slowly and carefully turn the port-relief adjusting screw (A) out (counterclockwise), a maximum of two turns, until the boom begins to lower. When the main boom begins to lower, STOP turning and let the boom descend slowly.

NOTE: Main boom motion can be stopped at any point by turning the relief screw (A) clockwise.

5. When the main boom has lowered and come to reset, reset the port-relief screw (A) to the position marked in step 2.

6. Tighten the port-relief screw jam nut (B), exercising care not to turn the port-relief screw (A).

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A-Port-Relief Adjusting Screw
B-Jam Nut

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