Generac Power Systems 3.9 User manual

3.9LITER
SERVICE
MANUAL
Manual Part No. 0E9755
CHRYSLER
GAS
ENGINE

FOREWORD
This manual has been published by GENERAC® POWER SYSTEMS,
INC. to aid our dealers’ mechanics, company service personnel and
general consumers when servicing the products described herein.
It is assumed that these personnel are familiar with the servicing
procedures for these products, or like or similar products, manufac-
tured and marketed by GENERAC® POWER SYSTEMS, INC. It is also
assumed that they have been trained in the recommended servicing
procedures for these products, which includes the use of mechanics
hand tools and any special tools that might be required.
Proper service and repair is important to the safe, economical and
reliable operation of the products described herein. The trou-
bleshooting, testing, service and repair procedures recommended by
GENERAC® POWER SYSTEMS, INC. and described in this manual are
effective methods of performing such operations. Some of these
operations or procedures may require the use of specialized equip-
ment. Such equipment should be used when and as recommended.
We could not possibly know of and advise the service trade of all
conceivable procedures or methods by which a service might be per-
formed, nor of any possible hazards and/or results of each proce-
dure or method. We have not undertaken any such wide evaluation.
Therefore, anyone who uses a procedure or method not recom-
mended by the manufacturer must first satisfy himself that neither
his safety, nor the product’s safety, will be endangered by the serv-
ice or operating procedure selected.
All information, illustrations and specifications contained in this
manual are based on the latest product information available at the
time of publication. However, GENERAC® POWER SYSTEMS, INC.
reserves the right to change, alter or otherwise improve the product
at any time without prior notice.
Some components or assemblies of the product described in this
manual may not be considered repairable. Disassembly, repair and
reassembly of such components may not be included in this manual.
The engines described herein may be used to power a wide variety
of products. Service and repair instructions relating to any such
products are not covered in this manual. For information pertaining
to use of these engines with other products, refer to any owner’s or
service manuals pertaining to said products.

This engine has been engineered for use in
Generac Power Systems products. The contents of
this manual have been reprinted from the original
manufacturer’s service and repair manual.
SERVICE RECOMMENDATIONS ................................................................................................................ A_2
CHRYSLER CONTENTS..........................................................................................................................................
3.9 Liter Gas Engine Table of Contents

3.9 Liter Gas Engine Service Recommendations
ENGINE OIL RECOMMENDATIONS
The unit has been filled with “break in” engine oil
at the factory. Use a high-quality detergent oil classi-
fied “For Service CC, SD, SE or SF.” Detergent oils
keep the engine cleaner and reduce carbon deposits.
Use oil having the following SAE viscosity rating,
based on the ambient temperature range anticipated
before the next oil change:
Engine Lubrication System:
Type of Oil Pump ............................................................................Gear
Oil Filter ..................................................................Full Flow, Cartridge
Crankcase Oil Capacity ..........................3.8 liters (4.0 U.S. quarts.)
COOLANT
Use a mixture of half low silicate, ethylene glycol base
antifreeze and half soft water. Use only soft water and
only low silicate antifreeze. If desired, you may add a
high quality rust inhibitor to the recommended
coolant mixture. When adding coolant, always add the
recommended 50-50 mixture.
Cooling System:
Type........................................................Pressurized, Closed Recovery
Coolant Capacity
System..............................................19.3 liters (5.0 U.S. gallons.)
Do not remove the radiator pressure cap while
the engine is hot or serious burns from boiling
liquid or steam could result.
Ethylene glycol base antifreeze is poisonous. Do
not use your mouth to siphon coolant from the
radiator, recovery bottle or any container. Wash
your hands thoroughly after handling. Never
store used antifreeze in an open container
because animals are attracted to the smell and
taste of antifreeze even though it is poisonous
to them.
Do not use any chromate base rust inhibitor with
ethylene glycol base antifreeze, or chromium
hydroxide (“green slime”) will form and cause
overheating. Engines that have been operated
with a chromate base rust inhibitor must be
chemically cleaned before adding ethylene glycol
base antifreeze. Using any high silicate antifreeze
boosters or additives also will cause overheating.
We also recommend that you DO NOT use any
soluble oil inhibitor for this equipment.
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!
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DANGER
◆
◆
Temperature Oil Grade (Recommended)
Above 80° F (27° C) SAE 15W-40
32º to 86º F (0º to 30º C) SAE 15W-40
Below 32º F (0º C) SAE 15W-40
A_2

3.9 Liter Gas Engine Service Recommendations
PERIODIC MAINTENANCE SCHEDULE:
A_3
SCHEDULED MAINTENANCE
Following is a recommended maintenance schedule for Generac small standby and residential generator sets.
The established intervals in the schedule are the maximum recommended when the unit is used in an aver-
age service application. They will need to be decreased (performed more frequently) if the unit is used in a
severe application. Use the unit hour meter or calendar time, whichever occurs first, from the previous main-
tenance interval to determine the next required maintenance interval.
Service Maintenance Interval Information:
The various service maintenance intervals are designated by interval numbers as follows:
1An early inspection of the generator set to ensure it is ready to operate when required and to identify any
potential problem areas.
Performed monthly or following each 10 hours of operation of the unit and requires approximately .5
man-hours per unit to complete.
This inspection may be performed by the end user providing the following safety steps are taken to pre-
vent the engine from starting automatically without warning:
To prevent injury, perform the following steps in the order indicated before starting any maintenance:
• Disable the generator set from starting and/or connecting to the load by setting the control panel
AUTO-OFF-MANUAL switch to the “OFF” position.
• Remove the control panel fuse.
• Turn off the battery charger.
• Remove the negative battery cable.
The battery charger must be turned off BEFORE removing the battery cable to prevent an over current con-
dition from burning out sensitive control panel components and circuits.
Following all maintenance, reverse these steps to insure the unit is returned to standby setup for normal
operation when required.
2A break-in service inspection of the generator set to ensure it is ready to operate and carry the load when
required, and to identify any potential problem areas.
Performed ONLY ONCE following the first three months or the first 30 hours of operation after purchase
of the unit and requires approximately 2.5 man-hours per unit to complete.
This inspection contains some maintenance tasks which require special tools, equipment, and/or knowl-
edge to accomplish and should be performed only by an authorized Generac Service Dealer.
3An operational inspection of the generator set to ensure it is ready to operate and carry the load when
required, and to identify any potential problem areas.
Performed semi-annually or following each 50 hours of operation of the unit and requires approximate-
ly 1.5 man-hours per unit to complete.
This inspection contains some maintenance tasks which require special tools, equipment, and/or knowl-
edge to accomplish and should be performed only by an authorized Generac Service Dealer.
4A mid-level inspection of the generator set to ensure it is ready to operate and carry the load when required,
and to identify any potential problem areas.
Performed annually or following each 100 hours of operation of the unit and requires approximately 4.0
man-hours per unit to complete.
This inspection contains some maintenance tasks which require special tools, equipment, and/or knowl-
edge to accomplish and should be performed only by an authorized Generac Service Dealer.

A_4
3.9 Liter Gas Engine Service Recommendations
Maintenance Level 1 Level 2 Level 3 Level 4
Tasks Recom- Task Required Task Required Task Task
mended Comp. to be done Comp. to be done Comp. Required Comp.
to be done (Date- 3 months/ (Date- Semi- (Date- to be done (Date-
monthly/ Initials) Break-in Initials) annually/ Initials) Annually/ Initials)
10 hrs. 30 hrs. 50 hrs. 100 hrs.
1. Disable the unit from
operating per the first page
warning.
2. Check the engine oil level.
Adjust as necessary.
3. Check the engine coolant
level. Adjust as necessary.
4. Check the engine coolant
thermal protection level.
Correct as necessary.
5. Check the natural gas
delivery system on gas
engine driven units.
Tighten connections as
necessary.
6. Check the air inlets and
outlets for debris. Clean as
necessary.
7. Check the battery
electrolyte level if
accessible. Adjust as
necessary.
8. Check the battery posts,
cables, and charger for
loose connections,
corrosion, and proper
operation. Correct as
necessary.
9. Check the unit wiring for
loose connections,
corrosion, and damage.
Correct as necessary.
10. Check the engine
accessory drive belts for
wear, weather cracking,
and damage. Replace as
necessary.
11. Visually inspect the unit
looking for leaks, wear or
damage, loose connections
or components, and
corrosion. Correct as
necessary.
12. Test the engine and
transfer switch safety
devices. Correct and/or
adjust as necessary.

A_5
3.9 Liter Gas Engine Service Recommendations
Maintenance Level 1 Level 2 Level 3 Level 4
Tasks Recom- Task Required Task Required Task Task
mended Comp. to be done Comp. to be done Comp. Required Comp.
to be done (Date- 3 months/ (Date- Semi- (Date- to be done (Date-
monthly/ Initials) Break-in Initials) annually/ Initials) Annually/ Initials)
10 hrs. 30 hrs. 50 hrs. 100 hrs.
13.Initiate an automatic start
and transfer of the unit to
site load and exercise it for
at least 1 hour looking for
leaks, loose connections
or components, and
abnormal operating
conditions. Correct as
necessary.
14. Start and exercise the unit
at full rated load (use a
load bank if the site load is
not enough) for at least 2
hours looking for leaks,
loose connections or
components, and abnormal
operating conditions.
Correct as necessary.
15. Change the engine oil.
16. Replace the engine oil
filter(s).
17. Replace the engine air
filter(s).
18. Replace the engine fuel
filter(s) on diesel engine
driven units and re-prime
the fuel system.
19. Check the engine spark
plugs on gas engine driven
units. Clean and re-gap or
replace as necessary.
20. Perform a 5 minute no-load
operational run of the unit
looking for any post service
problems.
21. Return the unit to standby
setup for operation when
required.