engagement. The other engine can then continue to
2. With the throttle in the stop position, rotate the
supply power to the gear box.
flywheel until one of the bolts aligns with the opening
in the flywheel housing.
CAUTION: When the shut-off lever is turned to
3. Remove the bolt from the flywheel.
the off position, lock it in that position by wire
or some other means to prevent vibration from
4. Remove and save the jam nut, and replace the bolt
moving it hack up to the on position. This
caution applies particularly when work is being
done on the engine.
5. Remove and reinstall the remaining two bolts in the
It is recommended that all sailing vessels and boats
utilizing the Torqmatic marine gears (single or twin
6. Start at the first bolt and tighten all three bolts
screw installations) have a locking (brake) device to
uniformly, thereby locking the clutch plate between
prevent the propeller shaft from rotating while the
the piston and the drive plate. Install the pipe plug in
sailing vessel is operating under sail, or the boat is
the flywheel housing.
operating with one engine shut down or being towed.
NOTE: To prevent binding between the piston
With the engine shut down. and the marine gear oil
and the bore in the flywheel, the emergency
pump not operating. it cannot circulate lubricating oil
engagement bolts must he tightened uniformly.
through the reverse gear. Therefore. overheating and
damage to the marine gear is possible unless rotation
CAUTION: To prevent damaging the gear. do
of the propeller shaft is prevented.
not use the reverse drive when the engagement
bolts are engaged.
If the clutches cannot be engaged hydraulically, in an
emergency, the forward drive may be engaged with
IMPORTANT: To reduce the possibility of
three bolts as follows.
overheating, add an additional gallon of oil if
t h e forward clutch is engaged with the
1. Remove the large pipe plug from the forward face
emergency engagement bolts and the hydraulic
of the flywheel housing.
pump is inoperative.
TWIN DISC MARINE GEAR
A Twin Disc marine gear is used on certain V-71
operating pressure to a point where the multi-disc
marine engines. This marine gear has two hydrauli-
clutch plates slip. Further movement of the valve
cally operated multi-disc clutches to provide forward
increases the slippage. This permits very low propeller
and reverse operation.
speeds necessary for some fishing operations. The
entire oil spill from the trolling valve, in dropping the
pressure, is directed through the plates of the forward
The marine gear has an oil sump capacity of
slipping clutch. This provides a film of oil on which
approximately six gallons (22.71 litres). An oil pump
the plates ride and removes any heat generated.
driven by the reverse shaft operates whenever the
engine is operating. This pump draws oil from the
The marine gear is driven by the engine through
sump through a suction strainer, protecting the pump
synthetic rubber caps molded in a gear tooth form.
from foreign particles in the oil. The oil discharged
The rubber caps are mounted on the teeth of the
from the pump flows through an oil cooler, mounted
spider gear and mesh with the flywheel drive ring.
on the side of the engine, and then returns to the
They cushion the drive from the engine to the marine
marine gear housing. The oil upon entering the gear
housing passes through an integral oil filter and then
to the selector valve. A by-pass valve across the filter
prevents the stoppage of oil flow to the selector valve
in the event the filter becomes clogged.
Some units incorporate a trolling valve which is
In case of emergency shifting from forward to reverse
mounted between the selector valve and the forward
at higher than normal engine speeds, the selector and
clutch. This valve is a relief valve with manual control
pressure regulating valve should have a 1/2 second
over the relief valve spring. Movement of the trolling
pause in neutral so that it can control the rate of
valve by the operator drops the forward clutch
pressure rise. This causes 3/4 to 1 1/2 second delay