Generac Power Systems GTH - 990, Owner'S Manual

1

INTRODUCTION

READ THIS MANUAL THOROUGHLY

If any portion of this manual is not understood, contact the nearest 

Dealer for starting, operating and servicing procedures.
Throughout this publication, and on tags and decals affixed to the 

equipment, DANGER, WARNING, CAUTION and NOTE blocks are 

used to alert personnel to special instructions about a particular 

operation that may be hazardous if performed incorrectly or care-

lessly. Observe them carefully. Their definitions are as follows:

INDICATES A HAZARDOUS SITUATION OR ACTION WHICH, IF 

NOT AVOIDED, WILL RESULT IN DEATH OR SERIOUS INJURY.

Indicates a hazardous situation or action which, if not 

avoided, could result in death or serious injury.

Indicates a hazardous situation or action which, if not 

avoided, could result in minor or moderate injury.

NOTE:

Notes contain additional information important to a procedure 

and will be found within the regular text body of this manual.

These safety warnings cannot eliminate the hazards that they 

indicate. Common sense and strict compliance with the special 

instructions while performing the action or service are essential to 

preventing accidents.
Four commonly used safety symbols accompany the 

DANGER

, 

WARNING

 and 

CAUTION

 blocks. The type of information each 

indicates is as follows:



 This symbol points out important safety information that, 

if not followed, could endanger personal safety and/or 

property of others.





This symbol points out potential explosion hazard.



This symbol points out potential fire hazard.



This symbol points out potential electrical shock hazard.

The operator is responsible for proper and safe use of the equip-

ment. The manufacturer strongly recommends that the operator 

read this 

Owner’s Manual

 and thoroughly understand all instruc-

tions before using this equipment. The manufacturer also strongly 

recommends instructing other users to properly start and operate 

the unit. This prepares them if they need to operate the equipment 

in an emergency.

RULES FOR SAFE OPERATION

Study these RULES FOR SAFE OPERATION carefully before 

operating or servicing this equipment. Become familiar with the 

OWNER’S MANUAL and with the engine. The engine can operate 

safely, efficiently and reliably only if it is properly operated and 

maintained. Many accidents are caused by failing to follow simple 

and fundamental rules or precautions.
The manufacturer cannot anticipate every possible circumstance 

that might involve a hazard. The warnings in this manual and 

on tags and decals affixed to the equipment, are therefore, not 

all-inclusive. If using a procedure, work method or operating 

technique the manufacturer does not specifically recommend, 

ensure that it is safe for others. Also make sure the procedure, 

work method or operating technique utilized does not render the 

engine to be unsafe.



 DO NOT tamper with the engine governed 

speed. High operating speeds are danger-

ous and increase the risk of personal injury 

or damage to the equipment. Operating at 

low speeds with heavy load may shorten the 

engine’s life.

BEFORE OPERATING

•  Gasoline is highly FLAMMABLE and its vapors are EXPLOSIVE. 

Do not permit smoking, open flames, sparks or heat in the area 

while handling gasoline. Avoid spilling gasoline on a hot engine. 

Comply with all of the laws regulating storage and handling of 

gasoline.

•  Store gasoline and other fuels only in containers designed and 

approved for the storage of such materials.

• Pressure can build up in the fuel tank. Loosen the fuel cap 

slowly to relieve any pressure in the tank.

• Add gasoline and other fuels in a clean, well-ventilated area. 

Wipe up any spilled gasoline immediately. If gasoline has been 

spilled, let it dry completely before starting the engine.

•  Do not overfill the fuel tank. Always allow room for fuel expan-

sion. If the tank is overfilled, the fuel can overflow onto a hot 

engine and cause a FIRE or an EXPLOSION.

• Thoroughly inspect the engine for loose or damaged parts 

before each use. Do not use the engine until adjustments or 

repairs are made.

•  Check the oil level in the engine before each use.
•  Inspect the engine periodically. Repair or replace all damaged or 

defective parts immediately.

•  Inspect fuel system frequently for leaks or damage. Repair or 

replace any damaged or leaking component immediately. Never 

attempt to change, alter or modify the engine fuel system in 

any way that might affect safety or compliance with applicable 

codes and standards.

Safety Rules