Onan J Series User Manual

GENERAL INFORMATION
FOREWORD
This manual covers the operation, maintenance and
service procedures for the two-cylinder, 60 cu.
in. 21.6
horsepower JB engine and the four-cylinder 120 cu.
in. 42.5 horsepower JC engine.
The two engines are very similar. Both are 4 cycle,
vertical, in-line, air-cooled engines with overhead
valves. Normal engine speed ranges up to
2700 rpm.
An internal, constant speed, flyball-type mechanical
governor, externally adjustable,
is standard. Optional
two-speed and variable-speed governors are
available.
Each engine is test-run at the factory for several hours
and adjusted for correct operation. Any damage
incurred through transit must be corrected before
operating the engine.
f
Unless specified, all instructions and procedures in
this manual apply to both the JB and JC. When
instructions apply to a specific engine model, refer to
the engine nameplate for the model and specification
'
number.
TABLE OF CONTENTS
General Information
.......................... 1
Specifications ................................ 2
Dimensions and Clearances.. ................. 3
Tune-up Specifications ....................... 4
Assembly Torques and Special Tools.. ........ 5
Optional Equipment .......................... 5
Installation ................................... 6
Operation .................................... 9
Troubleshooting Guide ....................... 12
Service and Maintenance ..................... 13
Cooling System .............................. 16
Fuel System.. ................................ 18
Ignition' System.. .............................. 30
Oil System ................................... 41
Flywheel Alternator. .......................... 50
Engine Disassembly and Repair ...............
Wiring Diagrams.. ............................ 66
Governor System.. ........................... 39
Starting System .............................. 44
55
1 WARNING)
EXHAUST GAS IS DEADLY!
Exhaust gases contain carbon monoxide, a poisonous gas that might cause
unconsciousness and death.
It is an odorless and colorless gas formed during
combustion of hydrocarbon fuels. Symptoms of carbon monoxide poisoning
are:
Dizziness Vomiting
Headache Muscular Twitching
Weakness and Sleepiness Throbbing in Temples
If you experience any of these symptoms, get out into fresh air immediately,
shut down the unit and do not use until it has been inspected.
The best protection against carbon monoxide inhalation is proper installation
and regular, frequent inspections of the complete exhaust system.
If you notice
a change
in the sound or appearance of exhaust system, shut the unit down
immediately and have it inspected and repaired at once by a competent
mechanic.
I
The engine exhaust from this product
contains chemicals known to the State
of California to cause cancer, birth
I defects or other reproductive harm.
1
Y
Redistribution or publication of this document, 
by any means, is strictly prohibited.

Onan J Series Specifications

General

Brand	Onan
Model	J Series
Category	Engine
Language	English