Guardian Technologies 4582 & 4987 Manual De Usuario

•  Loose cylinder head bolts.
•  Failed cylinder head gasket. 
•  Burned valves or valve seats.
•  Insufficient valve clearance.
•  Warped cylinder head.
•  Warped valve stem.
•  Worn or broken piston ring(s).
•  Worn or damaged cylinder bore.
•  Broken connecting rod.
•  Worn valve seats or valves.
•  Worn valve guides.
NOTE: Refer to Engine Service manual No. 0F6923 

If  the  engine  cranks  and  starts,  then  shuts  down 

almost immediately, the cause may be one or more of 

the following:
•  Low engine oil level.
•  Low oil pressure.
•  A defective oil pressure switch.

LOW OIL SWITCH

PROCEDURE:
1. Check engine crankcase oil level.

a. Check engine oil level.
b. If  necessary,  add  the  recommended  oil  to 

the  dipstick  FULL  mark.    DO  NOT  OVERFILL 

ABOVE THE FULL MARK.

2. Do the following:

a. Disconnect  Wire  86  and  Wire  0  from  the  oil 

pressure  switch  terminals.    Remove  the  switch 

and install an oil pressure gauge in its place.

b. Start the engine while observing the oil pressure 

reading on gauge.

c. Note the oil pressure.

(1)  Normal oil pressure is approximately 35-40 

psi with engine running.  If normal oil pres-

sure is indicated, go to Step 4 of this test.

(2)  If  oil  pressure  is  below  about  10  psi,  shut 

engine down immediately.  A problem exists 

in  the  engine  lubrication  system.  Refer  to 

Service  Manual,  Generac  P/N  0F6923  for 

engine service recommendations.

v-twin engines.
3. Remove  the  oil  pressure  gauge  and  reinstall  the  oil  pressure

switch. Do NOT connect Wire 86 or Wire 0 to the switch termi-
nals.

a. Set a voltmeter to measure resistance.
b. Connect the meter test leads across the switch 

terminals.    With  engine  shut  down,  the  meter 

should read CONTINUITY.

c.  Crank and start the engine.  The meter should 

read INFINITY.

d. Connect one test lead to Wire 0 ( disconnected from

LOP).  Connect  the  other  test  lead  to  a  clean  frame

ground. CONTINUITY should be measured. If CON-

TINUITY is NOT measured repair or replace Wire 0

between the LOP and the ground terminal connection

on the engine mount.

4. If the LOP switch tests good in Step 3 and oil pressure is good

in Step 2, but the unit still shuts down with a LOP fault, check
Wire  86  for  a  short  to  ground.  Set  a  voltmeter  to  measure
resistance. Disconnect the J2 Connector from the circuit board.
Remove Wire 86 from the LOP switch. Connect one test lead to
Wire 86. Connect the other test lead to a clean frame ground.
INFINITY  should  be  measured.  If  CONTINUITY  is  measured,
repair or replace Wire 86 between the LOP switch and the J2
Connector.

RESULTS:
1. If switch tests good, refer to Flow Chart.

2. Replace switch if it fails the test.

PROCEDURE:
1. Set a voltmeter to measure resistance.

2. Disconnect Wire  15  and Wire  229  from  the  Start  Stop  Relay

(SSR). See Figure 6-54.

3. Connect one meter test lead to the terminal that Wire 15 was

removed from. Connect the other meter test lead to the terminal
that Wire 229 was removed from. Resistance measured should
be approximately 100 ohms.

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