Usage:
This troubleshooting guide can be an aid for the serviceman to find the cause of existing problems. Several common problems are covered in the guide, but these problems are not arranged in any particular sequence.
Identify your particular type of problem from the Problem Index, then go directly to that problem in the guide. However, when you begin the procedure for that problem, start at Test Procedure Step 1 and follow through the step by step procedure. The steps in a particular problem provide a definite sequence to be followed for a logical, one by one elimination of many variables. These steps are arranged in order from the more probable/easiest to check, to the less probable/more complex to check.
Whenever the cause of the problem is found and corrected, stop the test (as shown by word STOP). Do not continue through the complete procedure just because it is there.
- 1. Engine Will Not Start (Engine Cranks But Does Not Start)*
- 2. Engine Will Not Start (Engine Does Not Crank)*
- 3. Engine Starts But Shutdown Occurs Immediately, Or Engine Shutdown Occurs While Still Cranking
- 4. Starter Remains Engaged Or Continues To Run After Engine Has Started
- 5. Engine Shutdown Occurs After Running More Than 3 Minutes
- 6. No Engine Shutdown When A Fault Occurs
- 2. Engine Will Not Start (Engine Does Not Crank)*
*Note: Be sure that the emergency stop pushbutton (ES), the remote normal stop switch (RNSS) and engine speed switch (ESS) have been reset and/or set in the RUN position. Also check and reset all circuit breakers on the front of the J box and the enclosure group.
Problem 1: Engine Cranks But Does Not Start
Crank the engine and observe the action of the governor and carburetor throttle.
If a 2301 or 2301A Electric Governor is used, measure the voltage supplied to the governor.
1. Carburetor Throttle And Governor Moves In Fuel On Direction.
The problem is in the engine ignition system or fuel system. Refer to engine portion of the Service Manual. STOP.
2. Carburetor Throttle Does Not Move.
Start-stop switch (SSS) not in START position when the engine is cranked. Go to Test Procedure Step 2.
3. If 2301 or 2301A Electric Governor Is Used And Supply Voltage Is Found To Be Greater Than 15 Volts.
Problem is in governor or actuator system. Refer to 2301 Electric Governor Service Manual, Form No. SENR2928 or to 2301A Electric Governor Service Manual, Form No. SENR3585. STOP.
4. If 2301 or 2301A Electric Governor Is Used And The Supply Voltage Is Found To Be Less Than 15 Volts.
Problem is in wiring to the 2301 or 2301A Electric Governor. Go to Test Procedure Step 3.
Connect a jumper between terminals TS11 and TS30 of the terminal strip in the J box and crank the engine. Reset circuit breaker CB7 and measure the voltage at TS11. Be prepared to use manual shutoff if needed.
1. Engine STARTS And Runs.
The SR1 relay was not energizing the gas shutoff valve (GSOV), 2301 or 2301A Electric Governor, if used. Go to Test Procedure Step 3.
2. Engine DOES NOT Start.
The GSOV is defective or stuck, or the throttle is stuck in the shutoff position. If there is no voltage at terminal TS11, circuit breaker CB7 may be open and should be reset or replaced. Find the source of the problem and correct. STOP.
Remove the jumper wire between terminals TS11 and TS30 that was connected in Test Procedure Step 2. Connect a jumper wire (in the J box) between terminals TS14 and TS24 of the terminal strip. Now crank the engine, but be prepared to use manual shutoff if needed.
1. Engine STARTS And Runs.
The SR1 relay is notdefective. Go to Test Procedure Step 4.
2. Engine DOES NOT Start.
The SR1 normally open contact stays open and is not energizing the GSOV or the 2301 or 2301A Electric Governor, if used. Replace the SR1 (see Procedure F) or repair any wiring problem. STOP.
Remove the jumper wire going from terminal TS14 to terminal TS24 of the SR1 relay that had been connected in Test Procedure Step 3. Connect a jumper between terminals TS9 and TS14 in the J box. Be sure that the emergency stop switch (ES) has been reset, and that the start-stop switch (SSS) and remote normal stop switch (RNSS) are in the RUN position, Crank the engine.
NOTE: For this test to be valid, oil pressure must be indicated when engine is cranked.
1. One Of The Switches Was In The STOP Position.
Problem has been solved. Disconnect the jumper across TS9 and TS14.
2. Engine Starts And Runs.
Problem is in the oil pressure switches (OPS1 or OPS2), the electronic speed switch (ESS) or the start-stop switch (SSS). Go to Test Procedure Step 7.
3. Engine DOES NOT Start.
Problem is not in oil pressure switches or in oil step pressure part of the electronic speed switch (ESS). Go to Test Procedure Step 8.
Be sure that the emergency stop pushbutton (ES) has been reset. Check the electronic speed switch (ESS) overspeed indicator light. Press the reset button if light is ON.
1. Engine Starts And Runs After Resetting ES Or ESS.
The ES or ESS needed to be reset. Problem has been solved. STOP.
2. Engine Starts And Runs, But ES Or ESS Did Not Require Resetting.
Problem is intermittent. Check the magneto wiring. STOP.
3. The Magneto Does Not Fire When The Engine Is Cranked.
Go to Test Procedure Step 6.
4. The Magneto Quits Firing During Cranking, Or Shortly After Starting, And The Overspeed Light Comes ON.
Engine is exceeding overspeed setting of the ESS. Recalibrate the ESS (see Service Procedure B). STOP.
5. The Magneto Quits Firing During Cranking, Or Shortly After Starting, And The Overspeed Light DOES NOT Come ON.
The emergency stop switch (ES) may be shorted or system wiring is incorrect. Check ES and wiring. Also check to see if the ESS overspeed contacts could be shorted. Repair or replace bad component(s). STOP.
Disconnect the wire going to terminal TS25 in the J box. Crank the engine.
1. The Engine Starts And Runs.
Problem is in the SR2 relay (see Procedure F) or the wiring to the SR2 relay. Reconnect wire at TS25.
2. Magneto Quits Firing Immediately After Starting Or During Cranking.
There is a problem in the magneto. Repair the problem. Reconnect wire at TS25. STOP.
Disconnect jumper wire that had been installed between terminals TS9 and TS14 in the J box while performing Test Procedure Step 4. Connect jumper wires across terminals 1 and 2 of oil pressure switches OPS1 and OPS2 (one switch at a time) and start the engine. Run engine at low idle speed.
NOTE: For this test to be valid, oil pressure must be indicated when engine is cranked and started.
1. The Engine STARTS And Runs When OPS1 Is Jumpered.
Replace the OPS1 switch (see Procedure G). STOP.
2. Engine DOES NOT START.
The electronic speed switch (ESS) is defective (normally closed OPSS contacts are open). Check ESS (see Procedure D) and, if necessary, replace ESS or correct wiring problems. Also check start-stop switch terminals SSS-10 and SSS-11. They may not be making contact in the START position. STOP.
3. The Engine Starts And Runs When OPS2 Is Jumpered.
The ESS (OPSS) speed setting is not correct (see Procedure C). STOP.
Remove the jumper between terminals TS9 and TS14 that was installed in Test Procedure Step 7. Now install jumpers on the J box terminal strip between terminals TS2 and TS3, TS3 and TS4 and between terminals TS4 and TS5. Crank the engine.
1. The Engine STARTSAnd Runs.
Either the water temperature switch (WTS) is open (temperature is too high), the air inlet temperature switch (AITS) is open (temperature is too high) or the remote normal stop switch (RNSS) is open (not making any contact) or is in the STOP position. Replace or repair component(s). STOP.
2. The Engine DOES NOT start.
Go to Test Procedure Step 9.
Remove the jumpers from the terminal strip in the J box between terminals TS2 and TS3 and between TS3 and TS4, if RNSS is used, between terminals TS4 and TS5. Now measure the voltage at terminals TS24 and TS2 and at terminals ESS-12 and ESS-9 of the electronic speed switch (measure these voltages before and while cranking the engine).
1. The Voltage At All Terminals Measured Is Low (Below 10 Volts).
Circuit breaker CB5 is open or there is no power going to J box. Reset CB5 or replace it if necessary. Correct wiring problem if CB5 is not at fault. STOP.
2. Before Cranking The Engine, The Voltage At Terminal TS24 Is Above 10 Volts, But The Voltage At Terminal ESS-12 Is Below 10 Volts.
The ESS crank terminate function is defective (see Procedure C). STOP.
3. Before Cranking The Engine, The Voltage At Terminal ESS-12 Is Above 10 Volts, But The Voltage At Terminal ESS-9 Is 2 Or More Volts LESS THAN The Voltage Measured At ESS-12.
The diode (D3) is open (see Service Procedure A).
4. While Cranking Engine, Voltage At Terminal ESS-12 Is Above 10 Volts, But Voltage At Terminal ESS-9 Drops When Crank Terminate Speed Setting Is Reached.
NOTE: When crank terminate speed setting is reached, starter motor will stop cranking. At this moment (if voltmeter is watched closely) voltage at ESS-9 will show a visible drop if one of the circuit components is defective.
The ESS overspeed switch is tripped and must be reset, or ESS is defective (see Procedure C). Also the diode (D2) may be defective (see Service Procedure A). STOP.
5. Starter Motor Does Not Stop Cranking (Crank Terminate Speed Not Reached).
Go to Test Result 6.
6. Voltages At Terminals TS24 And ESS-12 Are Above 10 Volts And Voltage At Terminal ESS-9 Is Within 2 Volts Of TS24 And ESS-12. The Voltage At TS2 Is Zero Or Is Less Than Voltage At ESS-9.
The ES switch is in the shutoff position or is defective. Reset or replace the ES switch. STOP.
7. Voltages At Terminals TS24 And ESS-12 Are Above 10 Volts, And Voltages At Terminals TS2 And ESS-9 Are Within 2 Volts Of Voltages At TS24 And ESS-12
The SSS switch is in the STOP position or is defective. Move SSS to RUN position or replace the switch. STOP.
Problem 2: Engine Does Not Crank
Be sure that the emergency stop switch (ES) has been reset. Wire a switch (2 amp. DC capacity) between terminals TS21 and TS26 of the J box. Close the switch momentarily, but do not start the engine.
A. Engine CRANKS.
The start-stop switch (SSS) or the remote start switch (RSS) (whichever switch did not work initially) is defective, or the wiring to the switch is defective. Replace or repair as appropriate. STOP.
2. Engine DOES NOT Crank.
Go to Test Procedure Step 2.
Connect the switch (used in Test Procedure Step 1) between terminals TS26 and TS24 of the J box. Close the switch momentarily, but do not start the engine.
1. Engine CRANKS.
The electronic speed switch (ESS) or the emergency stop switch (ES) is defective. Go to Test Procedure Step 3.
2. Engine DOES NOT Crank.
Reset the CB5 circuit breaker and try Test Procedure Step 2 again If it still does not crank, go to Test Procedure Step 4.
Connect The Switch (used in Test Procedure Steps 1 And 2) Between Terminal ESS-12 And Terminal TS26 In The J Box. Close The Switch Momentarily, But Do Not Start The Engine.
1. Engine CRANKS.
The emergency stop switch (ES) or the wiring to it is defective. Replace the ES switch or repair the wiring. STOP.
2. Engine DOES NOT Crank.
The electronic speed switch (ESS) or the wiring to it is defective. Replace the ESS or repair the wiring. STOP.
Check the voltage at terminal TS24 of the J box.
1. Voltage Is Low (1 To 20 Volts).
Charge the battery or repair loose connections between battery cable terminal and battery. STOP.
2. Voltage Is Above 20 Volts.
The engine mounted start switch (EMSS), magnetic switch (MS), pinion solenoid (PS) or starter motor (SM) is defective, or circuit breaker (CB2) must be reset. STOP.
3. Voltage Is Zero (Less Than 1 Volt).
Circuit breaker (CB5) is being overloaded or is defective. Locate and repair short circuit or overload, or replace CB5. STOP.
Problem 3: Engine Starts But Shutdown Occurs Immediately, Or Engine Shutdown Occurs While Still Cranking
Be sure that engine is full of oil, and also that oil pressure comes up during cranking. Connect a jumper between terminals TS9 and TS14 on the J box terminal strip, and start the engine.
1. Engine Starts And Continues To Run.
One of the oil pressure switches is causing the problem. Go to Problem 1, Test Procedure Step 7.
2. Engine Shutdown Occurs During Cranking Or Shortly After Starting.
Go to Test Procedure Step 2.
With the jumper between J box terminals TS9 and TS14 still connected, start the engine and measure the voltage on terminal TS14. Also note if the magneto quits firing.
1. Magneto Quits Firing
Go to Problem 1, Test Procedure Step 5.
2. Voltage Remains On Terminal TS14 When Engine Shutdown Occurs. Magneto Continues To Fire.
Go to Problem 1 and observe the action of the governor and throttle when shutdown occurs.
3. Voltage Goes To Zero On Terminal TS14 When Engine Shutdown Occurs.
The electronic speed switch (ESS) is defective (see Procedure C). If there is no defect in the crank terminate or the overspeed circuits of the ESS, check diode (D2) (see Procedure F). Also check for incorrect wiring.
Problem 4: Starter Remains Engaged Or Continues To Run After Engine Has Started
Measure voltages at terminals TS26 on the J box terminal strip and terminal ESS-12 on the electronic speed switch while the engine is running.
NOTE: When an engine mounted start switch (EMSS) is used, no testing is necessary. The EMSS is defective.
1. Zero Volts At Both Terminals TS26 In The J Box And Terminal 12 On The ESS
The problem is in the magnetic switch. Make repairs or replacement as necessary. STOP.
2. 15 To 32 Volts On Terminal 12 Of ESS (Voltage At TS26 Can Be Above Or Below 15 Volts).
The electronic speed switch (ESS) crank terminate (CT) contacts are not opening (see Procedure C). If the ESS is not defective, check diode (D3) (see Procedure F).
3. 15 To 32 Volts On Both Terminals TS26 And ESS-12.
Voltage at TS26: The start-stop switch (SSS) or the remote start switch (RSS) is closed. This is normal for an automatic start system. For a manual start system, these switches should open when released. Repair or replace switch. Voltage at ESS-12: the ESS (CT) contacts are not opening (see Procedure C).
Problem 5: Engine Shutdown Occurs After Running More Than 3 Minutes
Check overspeed indicator light on electronic speed switch (ESS).
1. Indicator Light Is ON .
Overspeed is indicated as cause of shutdown. Reset the ESS and find cause of overspeed. If ESS is found to be adjusted properly (see Procedure C) and problem occurs again, check the shielded cable. Only the shield must be connected to terminal 2 on ESS (see wiring diagram). STOP.
2. Indicator Light Is OFF.
Go to Test Procedure Step 2.
Connect a jumper wire between terminals TS9 and TS14 on the J box terminal strip. Start the engine.
1. Engine STARTS And Runs.
Problem is in oil pressure switches. Go to Problem 1, Test Procedure Step 7.
2. Engine STARTS But Shutdown Occurs Immediately.
Go to Problem 3, Test Procedure Step 1.
3. Engine STARTS And Runs, But Shutdown Occurs After Running 3 Minutes Or More.
Go to Test Procedure Step 3.
4. Engine Cranks But DOES NOT Start.
Go to Problem 1.
NOTE: If overheating or a defective temperature switch is suspected, go to Problem 1, Test Procedure Step 8. If temperature switch is not found to be the problem, go back to Problem 1, Test Procedure Step 1.
Disconnect the jumper wire installed in Test Procedure Step 2. Now connect a jumper wire between terminals TS14 and TS24 in the J box. Start the engine.
1. Engine STARTS And Runs
Go to Test Procedure Step 4
2. Engine Shutdown Occurs After Several Minutes.
Contacts of SR1 are opening intermittently, or problem is with the governor or engine fuel supply (see engine Service Manual). If a 2301 or 2301A Electric Governor is used, see 2301 Electric Governor Service Manual, Form No. SENR2928 or 2301A Electric Governor Service Manual, Form No. SENR3585. STOP.
Disconnect the jumper wire installed in Test Procedure Step 3. Now connect a jumper wire between terminals TS2 and TS5 of the J box. Start the engine.
1. Engine STARTS And Runs.
Power through the remote normal start switch (RNSS), water temperature switch, or a wire connection to these components is intermittent and causes the shutdown. Check continuity of switches and replace or tighten any loose wire connections. STOP.
2. Engine shutdown occurs after several minutes.
The start-stop switch (SSS), emergency stop switch (ES), electronic speed switch (ESS) contacts, diode (D2), or wiring to these contacts are intermittent. Tighten any loose wire connections and check all switches for continuity. STOP.
Problem 6: No Engine Shutdown When Fault Occurs.
Find the wire that connects terminal 4 of the SR1 relay to terminal TS14 on the J box terminal strip. Disconnect and insulate (tape) the wire end from terminal TS14. Now crank the engine.
1. Engine STARTS And Runs.
The SR1 relay is shorted or is stuck in the closed position (see Procedure G) or the Gas Shutoff Valve (GSOV) is stuck in the RUN position. STOP.
2. Engine Cranks But WILL NOT Start.
Go to Test Procedure Step 2.
To simulate a fault, start the engine and run at low idle. Now disconnect the fault switches as follows:
Disconnect OPS1 by unplugging the OPS1 connector.
Disconnect OPS2 (optional) by unplugging the OPS2 connector.
Disconnect WTS by unplugging the WTS connector.
Test overspeed switch (OS) by using 75% verify test (see Service Procedure A). Run engine at high idle and disconnect OPS2 to test oil step function.
Disconnect AITS by unplugging the AITS connector.
1. When OPS1 Or WTS Is Disconnected At Low Idle, Engine Shutdown Occurs.
Engine protection system is okay. Replace defective OPS1, AITS or WTS switch (see Procedures G, J and L). STOP.
2. When OPS2 Is Disconnected At Low Idle, The Engine Continues To Run. When The Engine Accelerates To High Idle (With OPS2 Still Disconnected), Engine Shutdown Occurs.
The engine protection system is okay. Check the OPS2 switch (see Procedure G). STOP.
3. Disconnecting WTS Or OPS1 Does Not Result In Engine Shutdown.
There is a wiring error that is shorting around these contactors. Find and correct this wiring problem. STOP.
4. When OPS2 Is Disconnected At High Idle, Engine Shutdown Does Not Occur.
The electronic speed switch (ESS) oil pressure step circuit, or the wiring to it, is defective (see Procedure C). Be sure that the ESS does have this oil pressure step function (ESS terminals 13, 14 and 15 will be identified if it does). STOP.
5. Overspeed Verify Test (See Service Procedure A) Does Not Result In Engine GSOV Shutdown.
The ESS overspeed (OS) contact may not be operating (see Service Procedure A). The diode D2 (see Procedure F) or wiring may be defective if ESS is found to be satisfactory. STOP.
6. Overspeed Verify Test Does Not Shutoff The Magneto.
The SR2 relay (see Procedure H), or the magneto is defective. Repair as necessary. STOP.