TESTING AND ADJUSTING
3. ENGINE OVERSPEEDS ON START
Fuel Control Linkage
Improper assembly after overhaul, linkage not free, bound up in
"FUEL ON" position, governor control lever not connected with
stop lever of fuel control linkage. Make repairs or replacements
High Idle Setting Incorrect
Start engine in mid speed position and make an adjustment of the
high idle setting.
Compensation Needle Valve Adjustment
Make an adjustment of the compensation needle valve to get
stable governor operation.
Incorrect Governor Oil Used
Oil viscosity is too high for ambient temperature starting
conditions. Change oil to correct weight as recommended for the
engine. In extreme low ambient temperatures DEXRON ATF can
be used in UG-8 Governors only.
Dirty Governor Oil (Woodward UG-8)
Oil is sludged slowing governor response. Oil should be changed
before it gets too thick. Drain and flush with diesel fuel and add
Governor Not Engaged In Drive Coupling
Make sure governor is driven by the engine. If necessary,
remove and install governor to make sure it is engaged correctly
with the governor drive. Also, check for worn or damaged drive
components in the governor and engine.
4. ENGINE SPEED DOES NOT HAVE STABILITY.
Air In Oil (Foam) in Governor Especially on Initial
Open compensation needle valve and let governor
Start With New Oil.
oscillate for several minutes until air is vented from governor.
Reset needle valve to approximately to 3/4 open. Also make
sure the correct grade of oil is used as recommended for the
Low Oil Level
Add oil to correct level in WOODWARD UG-8 GOVERNORS.
Check for leaks, especially at drive shaft. Check for plugged oil
supply passages for CATERPILLAR 3161 GOVERNORS.
Compensation Adjustments Incorrect
Needle valve should be approximately 1/2 to open.
Negative Speed Regulation (Engine Speeds Up
On governors with Isochronous droop setting, correct droop
With Load Addition)
setting on governor.
Linkage Is Binding, Or Worn With Flat Spots and
Inspect and repair or replace linkage as needed.
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