Generac Power Systems 04758-1 User Manual

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Section 5 — Troubleshooting 
Guardian Air-cooled 7 kW, 12 kW and 15 kW Generators
5.1 TROUBLESHOOTING 
GUIDE
PROBLEM
CAUSE
CORRECTION
The engine will not crank.
1. Fuse blown
1. Replace 15A fuse on generator
control panel.
2. Loose, corroded or defective
2. Tighten, clean or replace
battery cables
as necessary.
3. Defective starter contactor (7 kW) 3. *
4. Defective starter motor
4. *
5. Dead Battery
5. Charge or replace battery.
The engine cranks but 
1. Out of fuel
1. Replenish fuel.
will not start.
2. Defective fuel solenoid (FS)
2. *
3. Open #14 wire from 
3. *
engine control board
4. Defective spark plug(s)
4. Clean, re-gap or replace plug(s).
5. Valve lash out of adjustment.
5. Reset valve lash.
The engine starts hard
1. Air cleaner 
1. Check, replace air cleaner.
and runs rough.
plugged or damaged
2. Defective spark plug(s)
2. Clean, re-gap or replace plug(s).
3. Fuel regulator not set.
3. Set fuel regulator.
4. Fuel pressure incorrect.
4. Confirm fuel pressure is at 11”-14”
water column (0.4 psi - 0.5 psi).
The AUTO/OFF/MANUAL switch 
1. Defective switch
1. *
is set to OFF, but the engine
2. AUTO/OFF/MANUAL switch
2. *
continues to run.
wired incorrectly
3. Defective control board 
3. *
There is no AC output from 
1. Main line circuit breaker open
1. Reset circuit breaker 
the generator.
to ON (or closed).
2. Generator internal failure
2. *
There is no transfer to 
1. Defective transfer switch coil
1. *
standby after utility 
2. Defective transfer relay
2. *
source failure.
3. Transfer relay circuit open
3. *
4. Defective control logic board
4. *
Unit consumes large
1. Break-in procedure
1. *
amounts of oil.
not followed (see Section 3.1)
*Contact the nearest Generac Authorized Dealer for assistance.
Generac® Power Systems, Inc.
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