Briggs & Stratton 90000 series User manual

Operator’s Manual
BRIGGSandSTRATTON.com
ECopyright Briggs & Stratton Corporation
Milwaukee, Wisconsin 53201 U.S.A.
Form No. 277098-9/06
Printed in U.S.A.
Model 90000 I/C 475/525 Series
Power Built 475/525 Series

2
TABLE OF CONTENTS
Safety 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Information 4-5. . . . . . . . . . . . . . . . . . . . . . . . .
Oil 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting and Stopping 8. . . . . . . . . . . . . . . . . . . . . . . .
Maintenance 9-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service & Storage 13. . . . . . . . . . . . . . . . . . . . . . . . . .
Warranty Information 14-17. . . . . . . . . . . . . . . . . . . .
For replacement parts or technical assistance, record below the engine model, type, and code numbers along with the date of
purchase. These numbers are located on your engine (see the “Engine Information” page).
Date of purchase:
Engine model:
MM / DD / YYYY
Model: Code:Type:
BEFORE OPERATING ENGINE
•Read entire Operating & Maintenance Instructions
AND the instructions for the equipment this engine
powers.*
•Failure to follow instructions could result in serious
injury or death.
THE OPERATING & MAINTENANCE INSTRUC-
TIONS CONTAIN SAFETY INFORMATION TO
•Make you aware of hazards associated with engines
•Inform you of the risk of injury associated with those
hazards, and
•Tell you how to avoid or reduce the risk of injury.
*Briggs & Stratton does not necessarily know what equipment this engine will power. For that reason, you should carefully
read and understand the operating instructions for the equipment on which your engine is placed.
The safety alert symbol ( ) is used to identify safety
information about hazards that can result in personal injury.
A signal word (DANGER, WARNING, or CAUTION) is used
with the alert symbol to indicate the likelihood and the
potential severity of injury. In addition, a hazard symbol may
be used to represent the type of hazard.
DANGER indicates a hazard which, if not
avoided, will result in death or serious injury.
WARNING indicates a hazard which, if not
avoided, could result in death or serious injury.
CAUTION indicates a hazard which, if not
avoided, might result in minor or moderate
injury.
CAUTION,when used without the alert symbol,
indicates a situation that could result in damage
to the engine.
WARNING
The engine exhaust from this product
contains chemicals known to the
State of California to cause cancer,
birth defects, or other reproductive
harm.
HAZARD SYMBOLS AND MEANINGS
Explosion
Toxic Fumes
Moving Parts
ShockHot Surface
Kickback
Fire
THE INTERNATIONAL SYMBOLS USED
ON THE ENGINE OR
IN THIS MANUAL INCLUDE:
On Off
Fuel Shutoff
Read Owner’s
Manual
Stop Fuel
Choke
Safety Alert
Oil
Frostbite
Wear Eye Protection

3
SAFETY
Gasoline and its vapors are extremely
flammable and explosive.
Fire or explosion can cause severe burns
or death.
WARNING
WHEN ADDING FUEL
•Turn engine OFF and let engine cool at least 2
minutes before removing gas cap.
•Fill fuel tank outdoors or in well-ventilated area.
•Do not overfill fuel tank. Fill tank to approximately
1-1/2 inches below top of neck to allow for fuel
expansion.
•Keep gasoline away from sparks, open flames, pilot
lights, heat, and other ignition sources.
•Check fuel lines, tank, cap, and fittings frequently
for cracks or leaks. Replace if necessary.
WHEN STARTING ENGINE
•Make sure spark plug, muffler, fuel cap and air
cleaner are in place.
•Do not crank engine with spark plug removed.
•If fuel spills, wait until it evaporates before starting
engine.
•If engine floods, set choke to OPEN/RUN position,
place throttle in FAST and crank until engine starts.
WHEN OPERATING EQUIPMENT
•Do not tip engine or equipment at angle which
causes gasoline to spill.
•Do not choke carburetor to stop engine.
WHEN TRANSPORTING EQUIPMENT
•Transport with fuel tank EMPTY or with fuel shut-off
valve OFF.
WHEN STORING GASOLINE OR EQUIPMENT
WITH FUEL IN TANK
•Store away from furnaces, stoves, water heaters or
other appliances that have pilot light or other
ignition source because they can ignite gasoline
vapors.
Starting engine creates sparking.
Sparking can ignite nearby flammable
gases.
Explosion and fire could result.
WARNING
•If there is natural or LP gas leakage in area, do not
start engine.
•Do not use pressurized starting fluids because
vapors are flammable.
WARNING
Rapid retraction of starter cord (kickback) will
pull hand and arm toward engine faster than
you can let go.
Broken bones, fractures, bruises or sprains
could result.
•When starting engine, pull cord slowly until
resistance is felt, then pull rapidly.
•Remove all external equipment/engine loads
before starting engine.
•Direct coupled equipment components such as, but
not limited to, blades, impellors, pulleys, sprockets,
etc., must be securely attached.
WARNING
Rotating parts can contact or entangle
hands, feet, hair, clothing, or accessories.
Traumatic amputation or severe laceration
can result.
•Operate equipment with guards in place.
•Keep hands and feet away from rotating parts.
•Tie up long hair and remove jewelry.
•Do not wear loose-fitting clothing, dangling
drawstrings or items that could become caught.

4
SAFETY
Engines give off carbon monoxide, an
odorless, colorless, poison gas.
Breathing carbon monoxide can cause
nausea, fainting or death.
WARNING
•Start and run engine outdoors.
•Do not start or run engine in enclosed area, even if
doors or windows are open.
WARNING
Running engines produce heat. Engine
parts, especially muffler, become extremely
hot.
Severe thermal burns can occur on contact.
Combustible debris, such as leaves, grass,
brush, etc. can catch fire.
•Allow muffler, engine cylinder and fins to cool
before touching.
•Remove accumulated combustibles from muffler
area and cylinder area.
•Install and maintain in working order a spark
arrester before using equipment on forest-covered,
grass-covered, brush-covered unimproved land.
The state of California requires this (Section 4442
of the California Public Resources Code). Other
states may have similar laws. Federal laws apply
on federal land.
WARNING
Unintentional sparking can result in fire or
electric shock.
Unintentional start-up can result in en-
tanglement, traumatic amputation, or lac-
eration.
BEFORE PERFORMING ADJUSTMENTS OR
REPAIRS
•Disconnect spark plug wire and keep it away from
spark plug.
•Disconnect battery at negative terminal (only
engines with electric start).
WHEN TESTING FOR SPARK
•Use approved spark plug tester.
•Do not check for spark with spark plug removed.
ENGINE INFORMATION
TECHNICAL INFORMATION
Engine Power Rating Information
The gross power rating for individual gas engine models
is labeled in accordance with SAE (Society of Automotive
Engineers) code J1940 (Small Engine Power & Torque
Rating Procedure), and rating performance has been
obtained and corrected in accordance with SAE J1995
(Revision 2002-05). Actual gross engine power will be
lower and is affected by, among other things, ambient
operating conditions and engine-to-engine variability.
Given both the wide array of products on which engines
are placed and the variety of environmental issues
applicable to operating the equipment, the gas engine
will not develop the rated gross power when used in a
given piece of power equipment (actual “on-site” or net
horsepower). This difference is due to a variety of factors
including, but not limited to, accessories (air cleaner,
exhaust, charging, cooling, carburetor, fuel pump, etc.),
application limitations, ambient operating conditions
(temperature, humidity, altitude), and engine-to-engine
variability. Due to manufacturing and capacity limitations,
Briggs & Stratton may substitute an engine of higher
rated power for this Series engine.

5
ENGINE INFORMATION
1. Rope Handle for Rewind Starter
2. Oil Drain Plug
3. Choke Control Lever
4. Throttle Lever
5. Air Cleaner
6. Fuel Tank Cap
7. Spark Plug / Spark Plug Wire
8. Muffler
9. Engine Model Type Code
xxxxx xxxx xx xxxxxxxx
10. Stop Switch Wire (if equipped)
11. Oil Fill Cap
4
5
3
7
6
1
2
9
10
11
2
8
12. Fuel Fill
13. Throttle/Choke Control
14. Air Cleaner
15. Stop Switch
13
14
15
12
GENERAL INFORMATION
ENGINE MODEL
This is a single cylinder, L-head, air-cooled engine. It is a low emis-
sions engine.
MODEL 90000
Bore 2-9/16 in. (65.09 mm). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stroke 1-3/4 in. (44.45 mm). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Displacement 9.02 cu. in. (148.0 cc). . . . . . . . . . . . . . . . . . . . .
TUNE-UP SPECIFICATIONS
Armature air gap 0.006 −0.010 in. (0.15 −0.25 mm). . . . . . . . .
Spark plug gap 0.030 in. (0.76 mm). . . . . . . . . . . . . . . . . . . . . . .
Valve clearance with valve springs installed and piston 1/4 in.
(6 mm) past top dead center (check when engine is cold). See
Repair Manual P/N 270962.
Intake 0.005 −0.007 in. (0.13 −0.18 mm). . . . . . . . . . . . . . . . .
Exhaust 0.007 −0.009 in. (0.18 −0.23 mm). . . . . . . . . . . . . . .
For practical operation, the horsepower loading should not ex-
ceed 85% of rated horsepower. Engine power will decrease
3-1/2% for each 1,000 feet (300 meters) above sea level and 1%
for each 10°F (5.6°C) above 77°F (25°C). Engine will operate
satisfactorily at an angle up to 15°.

6
OIL
CAUTION: This engine is shipped from Briggs &
Stratton without oil. Check oil level before starting
engine. If you start the engine without oil, the engine
will be damaged beyond repair and will not be
covered under warranty.
Note: If this engine is equipped with gear reduction, gear
reduction case must be filled with oil prior to operating en-
gine. See gear reduction oil filling instructions on page 12.
OIL CAPACITY
The engine holds approximately 2/3 qt. (21 ozs; 0.6 liter).
TYPE OF OIL TO USE
•Use a high quality detergent oil classified “For Service
SF, SG, SH, SJ” or higher, such as Briggs & Stratton 30,
Part Number 100005 (20 oz) or 100028 (48 oz).
•Do not use special additives.
•Choose a viscosity according to the table opposite.
Note: Synthetic oil meeting ILSAC GF-2, API
certification mark and API service symbol
(shown at left) with “SJ/CF ENERGY CON-
SERVING” or higher, is an acceptable oil at all
temperatures. Use of synthetic oil does not
alter required oil change intervals.
°F-20 0 20 40 60 80 100
°C-30 -20 -10 0 10 20 30 40
STARTING TEMPERATURE RANGE ANTICIPATED BEFORE NEXT OIL CHANGE
*
**
32
*CAUTION: Air cooled engines run hotter than
automotive engines. The use of non-synthetic
multi-viscosity oils (5W-30, 10W-30, etc.) in
temperatures above 40°F (4°C) will result in higher
than normal oil consumption. When using a
multi-viscosity oil, check oil level more frequently.
** CAUTION: SAE 30 oil, if used below 40°F (4°C), will
result in hard starting and possible engine bore
damage due to inadequate lubrication.
SAE Viscosity Grades
CHECKING AND ADDING OIL
•Check oil level before starting the engine.
•Check level daily, or after every eight (8) hours.
•Keep oil level at FULL.
•Do not overfill.
[1] Place engine level and clean around oil fill area.
[2] Remove oil fill cap.
[3] Add oil, if needed.
[4] Pour slowly. Fill to point of overflowing.
[5] Replace and tighten oil fill cap.
OIL LEVEL
Oil Fill

7
FUEL
TYPE OF FUEL TO USE
•Use clean, fresh, regular unleaded gasoline with a
minimum of 77 octane. Fresh fuel prevents gum from
forming in the fuel system or on essential carburetor parts.
Purchase fuel in quantity that can be used within 30 days.
•Do not use gasoline which contains Methanol.
•Do not mix oil with gasoline.
•For engine protection use Briggs & Stratton Gasoline
Additive available from your Authorized Briggs &
Stratton Dealer (P/N 5041 or single use pouch).
•This engine is certified to operate on gasoline. Exhaust
Emission Control System: EM (Engine Modifications).
CAUTION: Some fuels, called oxygenated or reformu-
lated gasoline, are gasoline blended with alcohols or
ethers. Excessive amounts of these blends can damage
the fuel system or cause performance problems. If any
undesirable operating symptoms occur, use gasoline
with a lower percentage of alcohol or ether.
ADDING FUEL
WARNING
[1] Remove cap. Fill tank to
approximately 1/2 inch below
lowest portion of fill opening to
allow for fuel expansion. Be careful
not to overfill.
[2] Replace cap before starting.
Fuel Fill
•Fill fuel tank outdoors or in well-ventilated area, away
from sparks, open flames, pilot lights, heat, and other
ignition sources.
•If fuel spills, wait until it evaporates before starting
engine.
•Turn engine OFF and let engine cool at least 2
minutes before removing gas cap.

8
STARTING AND STOPPING
STARTING AND OPERATING TIPS
♦Store and fuel equipment in
level position.
♦Use fresh fuel. (See Fuel.)
♦Use correct type of oil for
expected starting tempera-
ture. (See Oil.)
♦Remove external equip-
ment/engine loads. (See
equipment operating
instructions.)
♦Periodically remove any de-
bris buildup from the ma-
chine. (See Maintenance.)
♦After engine has started, let
it warm up several seconds
to several minutes, depend-
ing on outside temperature.
♦For maximum performance
and life, operate engine with
choke in RUN and throttle in
FAST.
WARNING
•Do not use pressurized
starting fluids.
•Vapors are flammable.
REWIND (MANUAL) STARTER
TO START ENGINE
[1] Check oil level (see p. 8).
[2] Move throttle to FAST. Operate engine with throttle in
FAST.
[3] Move choke control lever to CHOKE.
[4] Move stop switch to ON
(if equipped).
[5] When starting engine, pull cord slowly until resistance
is felt, then pull rapidly.
[6] Allow engine to warm up.
Adjust Choke: Slowly adjust toward RUN position. Wait
until engine runs smoothly before each choke adjust-
ment.
WARNING
OIL LEVEL
OFF
ON
Stop Switch
Throttle
Choke
TO STOP ENGINE
[1] Move throttle control to SLOW,
then to STOP (if equipped).
[2] Push stop switch
(if equipped) to OFF.
CAUTION: Do not stop engine
by moving choke control to
CHOKE. Backfire, fire or engine
damage could occur. Stop Switch
OFF
ON
Throttle

9
MAINTENANCE
MAINTENANCE
Regular maintenance will improve the performance and
extend the life of the engine. See any Authorized Briggs &
Stratton Dealer for service. Use only genuine Briggs &
Stratton parts. Other parts may not perform as well,
may damage the engine, and may result in injury.In
addition, use of other parts may void your warranty.
EMISSION CONTROL
Maintenance, replacement or repair of the emission
control devices and systems may be performed by any
nonroad engine repair establishment or individual.
However, to obtain no charge repairs under the terms and
provisions of the Briggs & Stratton warranty statement, any
service or emission control part repair or replacement must
be performed by a factory authorized dealer.
Follow the instructions and schedules indicated below.
Task
Perform task at hourly
or calendar interval,
whichever comes first.
Every 8 Hours
or Daily
25 Hours or
Every Season
50 Hours or
Every Season
100 Hours or
Every Season
100-300 Hours
Check Oil Level 4
Change Oil 4*
Change oil in gear
reduction (if equipped) 4
Service air cleaner
pre-cleaner (if equipped) 4**
Service air cleaner car-
tridge (if not equipped
with pre-cleaner)
4**
Service air cleaner car-
tridge (if equipped with
pre-cleaner)
4**
Inspect spark arrester
(if equipped) 4
Replace spark plug 4
Clean cooling system 4**
Clean combustion
chamber 4
*Change oil after first 5 to 8 hours of use, then every
50 hours or every season. Change oil every 25 hours
when operating the engine under heavy load or in high
temperatures.
** Clean more often under dusty conditions or when
airborne debris is present. Replace air cleaner parts, if
very dirty.
CAUTION: Used oil is a hazardous waste product.
Dispose of used oil properly. Do not discard with
household waste. Check with your local authorities,
service center, or dealer for safe disposal/recycling
facilities.
CHANGING OIL
Change oil after first 5 hours of use.
WARNING
Typical Drain Plugs
1/4” HEX PIPE
OIL
DRAIN
PLUG
[1] Place engine level.
[2] Place engine level. Dis-
connect spark plug wire
and keep it away from
spark plug.
[3] With engine OFF but still warm remove oil drain
plug and drain oil into appropriate receptacle.
[4] Reinstall oil drain plug. Remove oil fill cap.
[5] Add about 2/3 quart (21 ounces; 0.6 liter) new oil.
Fill to point of overflowing.
[6] Replace oil fill cap.
OIL FILL
CAP
OIL LEVEL

10
MAINTENANCE
AIR CLEANER
CAUTION: Do not use pressurized air or solvents to
clean cartridge. Pressurized air can damage
cartridge; solvents will dissolve cartridge.
COVER
CARTRIDGE
BASE
To Remove
To Install
PUSH TABS IN
WHILE PULLING
ON COVER TO
REMOVE
COVER
REMOVING AND RE-INSTALLING AIR CLEANER
[1] Push in the tabs located on the sides of the air cleaner
cover, while pulling cover off.
[2] Remove cartridge carefully to prevent debris from
entering carburetor.
[3] Re-install new air cleaner assembly in base.
[4] Replace cover by snapping tabs back into place.
Pre-cleaner
To clean pre-cleaner (if equipped), separate it from
cartridge and wash in liquid detergent and water. Air dry
thoroughly. Do not oil. Re-install dry pre-cleaner on clean
cartridge.
CAUTION: Do not use pressurized air or solvents to
clean cartridge. Pressurized air can damage
cartridge; solvents will dissolve cartridge.
ÌÌÌÌÌÌÌÌÌ
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SCREWS
COVER
CARTRIDGE
P/N 491588
OR 5043
PRE-CLEANER
P/N 491435
BASE
REMOVING AND RE-INSTALLING AIR CLEANER
[1] Loosen screws and remove cover.
[2] Remove pre-cleaner (if equipped) and cartridge
carefully to prevent debris from entering carburetor.
[3] Re-install clean (or new) air cleaner assembly in base.
[4] Replace cover and tighten screws.