Zenith NA665 User manual

202892 Rev-13 Nov 24, 2020
Heavy Duty
Engine
Operator Manual
and Maintenance Log
ZPP NA665, NA690, TA690, & TA6120
Stationary & Constant-Speed Mobile Industrial Engines

202892 Rev-13 Nov 24, 2020

202892 Rev-13 Nov 24, 2020
Service Parts
To ensure that your engine continues to run reliably and
efficiently for as long as possible, use only genuine Zenith
Power Products (ZPP) parts.
For genuine ZPP service parts for your engine, or for
technical assistance in servicing your engine, call:
1-276-525-4760
Hours:
Monday-Thursday: 8:00 –5:00 Eastern Time
Friday: 8:00 – 12:00 Eastern Time
Maintenance Providers
Maintenance and repair services may be performed by
you or any qualified engine service provider that you
choose. However, your engine warranty does not cover
damage or failure caused by improper maintenance or
repairs.
Operators Manual & Maintenance Log Storage &
Use
Store this Operators Manual and Maintenance Log in a
safe, visible place by your engine. The maintenance log
must be updated whenever your engine is serviced.
Disclaimer
All information and specifications in this manual are
based on the latest data available at the time of the
publication. Zenith Power Products reserves the right to
make changes or improvements at any time without
notice.
For additional information, see:
www.ZenithPP.com

1Rev-13 Nov 23, 2020
TABLE OF CONTENTS
Page
U.S. EPA Legal Requirements
2
Safety Symbols & Precautions
3
Fuels
6
Starting, running, and stopping the engine
7
Engine maintenance
•Schedule
•ECM Identification
•Air filter
•Battery
•CCV system
•Engine coolant, radiator, and cooling
system
•Accessory drive belts
•Electrical connections
•Engine oil & filters
•Checking for gas leaks
•Natural Gas & LPG fuel lock-off valves
•Pre- & Post-cat oxygen sensors
•Spark plugs & wires
9
Diagnostics
•How to retrieve fault codes
•Fault Code List
24
Specifications
32
Common Components
35
Engine Warranty
•Warranty provisions
•Base warranty period
•Emissions-related warranty period
•Owner's obligations
•Component lists
36
Engine Identification
39
Maintenance Log
40
Engine Installation Guide
49
Engine Misfire Troubleshooting
Appendix – Engines equipped with Dynagen
Controls
48

2Rev-13 Nov 23, 2020
U.S. EPA Legal Requirements
The ZPP NA665, NA690, TA690, and TA6120 Natural Gas and LPG
engines have been certified by the U.S. Environmental Protection
Agency (EPA) as stationary and mobile constant-speed engines. It is
illegal to operate these engines in a variable-speed (foot pedal speed
control) application.
To ensure emissions compliance, the U.S. EPA requires you
to do one of the following two options:
1. Operate and maintain your engine as specified in this
Operators Manual. In addition, you are required by law
to keep detailed maintenance records.
2. If you do not operate and maintain your engine as
specified in this Operators Manual, your engine will be
considered a non-certified engine.
In this case, you must:
•Keep a maintenance plan and records of conducted
maintenance.
•To the extent practicable, maintain and operate the
engine in a manner consistent with good air pollution
control practice for minimizing emissions.
•Conduct an initial performance test within 1 year of
engine startup to demonstrate compliance. Contact
your regional EPA office for instructions on how to
conduct an initial performance test.
Per section 113 of the U.S. Clean Air Act, failure to abide by
these legal requirements can result in fines up to $30,750 per
day.
A maintenance plan and log are provided at the back of this
manual for you to record your engine maintenance. Update
the log each time you service your engine.

3Rev-13 Nov 23, 2020
SAFETY SYMBOLS
This section identifies the ISO 8999 symbols that may be
used in this manual.
Battery
Electrical
hazards
Engine
coolant
fill level
Engine
coolant
temperatur
e
Engine
oil fill
level
Engine oil
pressure
Hot
surface
warning
Warning
Read the
handboo
k
No
Smoking or
Flame

4Rev-13 Nov 23, 2020
SAFETY PRECAUTIONS - STARTING
WARNING
Starting an engine incorrectly may cause injury to
the operator
and/or cause damage to the engine.
Engine operators must be instructed in the correct
procedures before attempting to start any engine.
Before Starting
.
•Inspect the engine, intake, exhaust, cooling system,
and drivetrain to verify that the engine is fully
assembled and not in the process of being serviced.
•Ensure the engine is free to turn without obstruction.
•Check that all safety guards are in their correct
position and secure.
•Check that the coolant level in the radiator
•Check that the oil level on the dipstick is between
"Add" and "Full".
•Check that the fuel supply is connected, shut-off
valves are open, and there are no leaks.
•If a LPG fuel system is being used, verify that there
is fuel in the tank.
•If a natural gas fuel system is being used, verify that
the correct fuel supply pressure is being supplied to
the engine.
•Check that the battery is connected and charged.
•When possible, disengage any driven equipment
while starting.

5Rev-13 Nov 23, 2020
SAFETY PRECAUTIONS – ELECTRICAL
The battery produces flammable and explosive
hydrogen gas. The battery electrolyte contains
poisonous and corrosive sulfuric acid. The
precautions listed below must be followed to
ensure operator safety.
•Do not smoke or allow any flame near the battery.
•With the engine stopped and the ignition switch in the
OFF position, disconnect the negative battery cable
from the battery before working on the engine.
•Be careful not to short circuit battery positive to
ground with tools when working on the engine.
•Avoid getting battery electrolyte in your eyes or on your
skin or clothes. If electrolyte gets in your eyes, flush
with clean water immediately and get medical help. If
electrolyte gets on your skin, wash immediately with
soap and water and get medical help if you feel pain or
burning. Remove and wash any clothing that is
exposed to electrolyte.
•Never remove any electrical cables while the battery
is connected in the circuit.
•Be careful to not short-circuit or cross battery positive
and negative.
•Never ‘flash’ any connection to check the current flow.
•The battery and alternator must be disconnected
before commencing any electric welding when a pole
strap is directly or indirectly connected to the engine.
•When charging the battery, only do a slow charge (5
A or less), and ensure there is good ventilation.

6Rev-13 Nov 23, 2020
FUELS
Natural gas and LPG are combustible gases, and can be
explosive if leaked and contained in a confined area. Keep
cigarettes and all other flame sources away from these
areas.
If you can hear a fuel leak, shut off the fuel supply at the
source immediatel
y and fix the leak or have it serviced.
Check the entire fuel supply line from the cylinder/tank to
the engine for leaks with a soapy water bubble mixture
anytime a cylinder/tank is changed or the fuel supply line is
worked on. Fuel leaks should also be checked as part of th
regular engine maintenance.
Depending on your engine and fuel system configuration, your engine is
designed to run on natural gas and/or vapor LPG. The fuel requirements for
each are discussed below. See the "SPECIFICATIONS" section for the
required fuel supply pressures for each fuel.
Natural Gas
Your engine is certified to run on "pipeline-quality natural gas". EPA defines
pipeline-quality natural gas as being composed of at least 70% methane by
volume or having a heating value of 950-1100 BTUs per cubic foot. In
addition, pipeline-quality natural gas must be provided by a supplier
through a pipeline. If your natural gas supply does not meet these
specifications, your engine is considered to be being operated as a non-
certified engine. See "U.S. EPA Legal Requirements" at the front of this
manual.
LPG
In order to maintain emissions compliance and your engine warranty, use
commercial-grade HD-10 or better LPG.
A liquid withdrawal system is recommended when there is insufficient LPG
vapor generated in the storage tank to supply the engine sufficient fuel to
maintain maximum power at the ambient temperature the engine is operating
in. (see engine data sheet) In a liquid withdrawal system Liquid LPG is drawn
off of the bottom side of a LPG tank and it remains a liquid until it has passed
through the vaporizer/regulator, at which point it is vaporized to a gas. If you
connect vapor LPG to a liquid LPG fuel system, you may starve the engine for
fuel, causing it to produce low power and excessive emissions.
In a vapor withdrawal LPG system, LPG is drawn off of the top side of a LPG
tank and is a gas from the tank through to the engine intake. If you connect
liquid LPG to a vapor LPG fuel system the fuel will not vaporize properly,
causing the engine to run rich, produce low power and excessive emissions.

7Rev-13 Nov 23, 2020
STARTING, RUNNING, & STOPPING THE
ENGINE
Observe the safety precautions listed in "SAFETY
PRECAUTIONS - STARTING" before starting the
engine.
Starting the engine
•Turn the key switch to the ON position and verify
that the MIL is illuminated. If not determine why
the lamp is not working.
•For initial startup on new engines, disable the
fuel lock-off and crank the engine for 15 seconds
to allow engine oil to circulate the engine before
starting. Enable the fuel lock-off.
•Turn the key switch to the START position and
hold until the engine has started.
•Release the key promptly after the engine starts
to avoid grinding the starter.
•Do not crank the engine for more than 15
seconds at a time.
•Allow at least 30 seconds between cranking
attempts.
•If the engine does not start after 3 starting
attempts, review the "Before Starting" checklist.

8Rev-13 Nov 23, 2020
Running the engine
•Idle the engine during the first 3 minutes of
operation. Do not fully load until coolant level
reaches 167 deg. F (75 deg. C).ª
•Verify that the "CHECK ENGINE" light is off
while the engine is running. If it is on, refer to
the DIAGNOSTICS section.
•Verify that there are no fuel, coolant, or oil leaks
while the engine is running. If there are leaks,
stop the engine and fix them or have the engine
serviced.
•Listen to the engine. If you hear an abnormal
noise while the engine is running, turn it off and
correct the problem or have the engine serviced.
*No adjustments are necessary to the fuel or ignition
systems.
Stopping the engine
•If the engine has been running under load and is
hot, run the engine at no load for 3 minutes to
allow the engine to cool before stopping the
engine.
•Stop the engine by turning the key switch to the
OFF position. The engine may run-on for 1-5
seconds while the fuel is depleted from the
intake manifold.
ªException: Unless the engine is used in “Emergency
Standby” operation.

9Rev-13 Nov 23, 2020
ENGINE MAINTENANCE
You should properly maintain your engine for the
following reasons.
•You are legally required to maintain your engine
and keep maintenance records to ensure
emissions compliance. See "U.S. EPA Legal
Requirements" at the front of this manual.
•Your engine warranty will be void if the engine is
not properly maintained.
•Keeping your engine properly maintained will
ensure the best engine life, power, and fuel
economy.
Scheduled Maintenance
A schedule of the required engine maintenance tasks is
listed on the following page. The scheduled
maintenance should be performed when the engine
reaches the specified operating hours or the specified
months have elapsed, whichever comes first.
Daily Maintenance
In addition to the scheduled maintenance, daily checks
are required to keep your engine running properly.
These checks are listed in the "SAFETY
PRECAUTIONS - STARTING" and "STARTING,
RUNNING, & STOPPING THE ENGINE" sections.
Maintenance Log
Keep a record of your engine's scheduled maintenance
in the Maintenance Log at the back of this manual.

10 Rev-13 Nov 23, 2020
48 AND 70 PIN ECM’s
During the 2017-2018 model years, ZPP’s NA665,
NA690, and TA690 will transition from a 48-pin ECM to a
70-pin ECM. It is important to know which ECM you have
on your engine, as the ECM determines the control
system voltage, the type of pre-cat oxygen sensor, and
knock sensing. The ECM’s, voltages, and pre-cat oxygen
sensors are not interchangeable or upgradeable. Using
the wrong ECM, voltage, or pre-cat oxygen sensor may
damage your engine’s control system. See Figure 1
Please see Common Parts (Figure 2) for associated
service part numbers.
48-pin ECM: 201407
70-pin ECM: 201408
Starting &
Charging
Voltage 24 VDC 24 VDC
Control
System
Voltage
12 VDC 24 VDC
Knock
sensors for
TA690 &
TA6120?
No Yes
Figure 1

11 Rev-13 Nov 23, 2020

12 Rev-13 Nov 23, 2020
AIR FILTER
Engine
Element
Part Number
NA665/NA690
Primary
200469
Secondary
200289
TA690
Primary
202186
Secondary
201050
TA6120
Primary
202519
Inspection
1. Remove air filter element from enclosure.
2. Tap filter to knock off loose dirt.
3. Visually check filter.
4. If filter is clean, reinstall old filter.
If filter is dirty, replace with a new filter.

13 Rev-13 Nov 23, 2020
BATTERY
The battery produces flammable and explosive
hydrogen gas. The battery electrolyte contains
poisonous and corrosive sulfuric acid. Review the
safety precautions in "SAFETY PRECAUTIONS -
ELECTRICAL" before working on the battery.
Battery Specifications
Nominal Voltage:
24 V
Cranking Amps:
1200
Cold Cranking Amps:
1000
Battery voltage during alternator charging:
28.6 V
Fully charged battery with key off @ 20° C (68° F):
27.2 V
Amp Hours (AH)
180
See “System Voltages” (Control System and
Starting/Charging System) in “Engine Specifications”
Pages 19-20.
Battery electrolyte inspection
1. Check electrolyte level.
2. If low, top off with distilled water. Do not overfill.
Battery corrosion inspection
1. Check battery posts and clamps for corrosion.
2. If corroded, remove negative cable first, then positive.
3. Clean both posts and both clamps with a small wire
brush.
4. Reconnect cables, positive cable first.
If the engine is cranking slowly or not at all:
1. Remove the battery negative lead from the battery.
2. Remove the positive lead from the battery.
3. Clean the battery posts and cables with a small wire
brush.
4. Replace leads, positive lead first.
If the engine is still cranking slowly or not at all:
1. Remove the battery negative leads.
2. Recharge the battery in a well-ventilated area.
3. Reinstall the battery.
If the engine is still cranking slowly or not at all:
Replace the battery.

14 Rev-13 Nov 23, 2020
CCV SYSTEM:
NA665, NA690, & TA690 Engines
Cartridge Part Number: 200584
TA6120 Engine
Cartridge Part Number: 202541
The crankcase ventilation system processes the
crankcase blow-by gases and oils in the filtration system.
Gases are delivered to the intake air to be combusted in
the engine. Oils which have been separated from the
blow-by gases are returned to the oil pan.
Service the CCV system at the intervals prescribed in
the Maintenance schedule (page 11), or more frequently
in freezing temperatures.
During Cold weather operation CCV system
can become plugged with freezing
condensation and emulsion from crankcase
blow-by. Preventative measures in addition to frequent
inspection are necessary to avoid damage to engine and
fuel system components.

15 Rev-13 Nov 23, 2020
ENGINE COOLANT, RADIATOR, AND
COOLING SYSTEM
To avoid being scalded or burned, never remove
the radiator cap unless the engine is off and
coolant has fully cooled. The coolant in the
radiator is pressurized when hot and may boil
over when the radiator cap is loosened.
When using antifreeze coolant, mix the antifreeze coolant
with water, observing instructions attached to antifreeze
container. Use only antifreeze approved for aluminum
components in a 50/50 mixture ratio.
Clean radiator outside
Clean outside of radiator with dry compressed air.
Inspect cooling system, hoses and connections
Check hoses and fittings for loose connections or for any
sign of oil deterioration or soft spots in the hoses.
Retighten connections or replace hoses if needed.
Check coolant level. If low, top off coolant with a premixed
50/50 mixture of antifreeze and water.
Engine Coolant Replacement
1. Open Degas tank cap.
2. Drain old coolant.
3. Flush system with fresh, clean water.
4. Slowly refill system with premixed 50/50
antifreeze/water mixture.
5. Idle engine with radiator cap off to allow air to
escape.
6. Stop engine.
7. Replace radiator cap and close overflow bottle
cap.

16 Rev-13 Nov 23, 2020
ACCESSORY DRIVE BELTS
Engine
Belt P/N
# per Engine
NA665
202334
1
NA/TA690
200577
1
TA6120
202544 - Alt/WP
202545 - Fan 2
Inspection
Check the belt for visible cracks, missing chunks, and
fraying. Small cracks on the inside of the belt are OK.
Replace the belt if cracks are visible on the outside of
the belt, chunks are missing from the inside of the belt,
or the belt is frayed.
Belt Tension
Measure the belt tension midway between the alternator
and water pump pulley as specified by the arrow in the left
figure above. Use a tensioning tool such as the one shown
in the right figure above (OTC 6673LG or equivalent).
Deflection:
A second method of measuring belt tension is to apply a
force of 50N (5kg, 11lb), and measure the deflection
between the alternator and Crankshaft pulley. If the belt
tension is not as specified, adjust it.
DEFLECTION
10 ~ 20 mm (0.390 ~ 0.780 in.)
NOTE:
"New belt" refers to a belt which has been used less than
5 minutes on a running engine.
"Used belt" refers to a belt which has been used on a
running engine for 5 minutes or more. After installing a belt,
check that it fits properly in the ribbed grooves. Check with
your hand to confirm that the belt has not slipped out of the
groove on the bottom of the pulley. After installing a new
belt, run the engine for about 5 minutes and recheck the
belt tension.
Belt Replacement
1. Release all tension from the old belt.
2. Remove the old belt.
3. Install the new belt.
4. Apply tension to the belt as specified in "Belt
Tension".
5. Recheck tension after 1 hour of operation.
6.

17 Rev-13 Nov 23, 2020
ELECTRICAL CONNECTIONS
1. Visually inspect the electrical
connections in the wiring harness for
loose connections.
2. If you see a loose connection, or
suspect a loose connection for other
reasons, take the connection apart.
3. Visually inspect the pins in the male
connector and the sockets in the female
connector.
4. If any pins or sockets are bent, recessed,
or corroded, repair the connector.
5. Remake the connection. Verify that the
connection is fully made and is snug
and secure.