2-10. Operating the Mixer
When operating with DRY MIX, disengage water pump drive belt to prevent
overheating and seizure of water pump A bearings.
b. After engine warm-up, pull out the governor control (fig. 2-5A) until engine is running at operating
speed (1600 RPM), then lock the governor control in position.
c. Engage the master clutch (fig. 2-5B) to revolve drum.
d. Load the skip with the stone or gravel first, then the sand, and then the cement. On very windy days,
load the stone first, then the cement, and the sand last to hold down the cement dust.
e. Engage the skip clutch (fig. 2-5D) easily but firmly.
Be sure to let go of the clutch lever once the clutch is engaged. When the top
position of the skip is reached, the clutch disengages automatically, as the skip
touches the knock-out lever. The skip brake grabs automatically as the clutch is
disengaged and holds the skip in position until the brake is released.
f. Immediately after engaging the skip clutch, move the water valve wrench (fig. 2-5F) to the
"Discharge-to-Drum" position. This lets some of the water into the drum before the materials slide out of the
skip. This should permit some of the water to be flowing into the drum after the materials are all in. The timing
of the water flow is very important and it is absolutely necessary to have some of the water going in ahead of
the materials. It is also necessary to have the water going into the drum up to one side of the opening ahead of
the materials. Never allow the water line to discharge directly into the middle of the drum. After the water flow
into the drum has stopped, move the water valve wrench to the "Fill Tank" position.
g. Lower the skip by releasing the skip brake (fig. 2-SD). Engage the skip brake again just before the
skip touches the ground. Let the skip down the rest of the way gently to prevent fouling of the cable on the
h. Mixing-It generally takes about 60 seconds per batch for a thorough mix, and less time will result in a
poor grade of concrete. If a very low slump or dry concrete is being mixed, it may require a few seconds longer
i. Discharge the batch from the drum
by revolving the hand wheel control (fig. 2-5) clockwise.
to reverse the discharge sprout before starting the skip up for charging the next batch.
j. When the pour has been finished, stop the engine (para 2-9).
k. When a pour has been finished, wash out the drum immediately because concrete tends to dry on the
inside and stick to the steel. Use a hose or brush on the outside of the mixer every time the inside is cleaned.
If the job is such that the mixer is in operation only now and then and is allowed to stand idle between batches,
the drum should be washed out after the last batch unless the next pour is going to be started within an hour.
This is especially true when heated materials are being used.
Section V. OPERATION UNDER UNUSUAL CONDITIONS
2-11. Operation in Extreme Cold
a. Lubrication. Lubricate in accordance with current lubrication order. Allow a longer time for warming
up the engine to insure adequate lubrication reaching vital working parts.
b. Fuel System. Keep fuel tank full when not in operation.
c. Electrical System. Move wiring as little as possible to avoid damaging wire insulation. Keep batteries
fully charged. After adding water to the batteries, run the engine for at least one hour.
d. Water System. Drain the water tank and pump after the last pour (of the day to prevent damage from
2-12. Operation in Extreme Heat
in accordance with current lubrication order. Check the engine crankcase oil
level frequently and keep level to FULL mark on oil gauge saber.
b. Electrical System. Check the batteries frequently for loss
of water due
c. Fuel System. Fill the fuel tank at the end of each day's operation to prevent accumulation of vapor
overnight. Make sure the oil in the air cleaner is at a proper level and is clean.
2-13. Operation in Dusty or Sandy Areas
a. Lubrication. Clean lubrication fittings before using grease gun. Clean fittings after lubrication.