912 Owner’s Manual
8/31/21
Page
5
of
16
CHAIN INSTALLATION
1. Slide chain under sprocket, with teeth in the correct cutting direction. Properly
installed, the cutting edges of the chain will face forward on the top of the boom and
rearward on the bottom of the boom (see diagram below).
2. Push digging boom control lever forward to lower boom onto the chain.
3. Wrap chain around boom and sprocket. Install chain master link or link pin.
4. Use boom adjuster screw to tighten chain. Chain should have enough slack to allow
approximately 1" to 2" of space between middle of boom and chain when boom and
chain are straight out in a horizontal position.
5. Tighten adjuster screw locknut.
Forward Cutting edge
Cutting edge Rearward
MAINTENANCE PREPARATION
Only trained & qualified personnel should perform maintenance or repairs of the trencher. Before
performing any service, maintenance, adjustments, repairs, or off-season long-term storage,
follow the SHUT DOWN PROCEDURE in the OPERATOR’S MANUAL.
Do not touch the engine, muffler, or any of the hydraulic components until cool.
WARNING
: Muffler and engine get hot enough to cause serious burns. For the
safety of yourself and others, allow enough time for the engine, muffler, and the
hydraulic fluid to cool completely before performing any cleaning or maintenance.
Avoid contact with hydraulic fluid.
WARNING
: When machine is operating, hydraulic fluid is under extreme pressure and
can get under skin and burn or poison.
If you need to lower the dig chain boom without power, do the following:
1.
Position a pan under the trencher to catch hydraulic fluid.
2.
Support the boom front end with a hoist or forklift.
WARNING
: The boom with dig chain is heavy. Manpower alone is not recommended,
but if necessary, use a team of two strong workers to support the boom, and a third
worker to loosen the hose.
3.
Loosen the hose at the rod end (front) port of the boom cylinder and lower the boom.
4.
If it still will not lower, then loosen the hose at the back end port of the boom cylinder.
