Genex SG7600EX Owner's Manual page 20

PRE-OPERATION CHECK
Occasionally you may hear light "spark knock" or "pinging" (metallic rapping
noise) while operating under heavy loads. This is no cause for concern.
If spark knock or pinging occurs at a steady engine speed, under normal load,
change brands of gasoline. If spark knock or pinging persists, see an authorized
GENEX generator dealer.
Running the engine with persistent spark knock or pinging can
cause engine damage.
Running the engine with persistent spark knock or pinging is misuse, and the
Distributor's Limited Warranty does not cover parts damaged by misuse.
Oxygenated Fuels
Some gasoline is being blended with alcohol or an ether compound to increase the
octane.
The gasoline is collectively referred to as oxygenated fuels. Some areas of the United States use
oxygenated fuels to help meet clean air standards.
If you use an oxygenated fuel, be sure its pump octane rating is 86 or higher.
Ethanol (ethyl or grain alcohol)
Gasoline containing more that 10% ethanol by volume may cause starting and/or
performance problems. Gasoline containing ethanol may be marketed under the name
"Gasohol".
Methanol (methyl or wood alcohol)
Gasoline containing methanol must contain co-solvents and corrosion inhibitors to protect
the fuel system. Gasoline containing more than 5% methanol by volume may cause
starting and/or performance problems and may damage metal, rubber and plastic parts of
your fuel system.
MTBE (methyl tertiary butyl ether)
You may use gasoline containing up to 15% MTBE by volume.
Before suing an oxygenated fuel, try to confirm the fuel's contents. Some states require this
information to be posted on the pump. If you notice any undesirable operating symptoms,
switch to conventional unleaded gasoline. Fuel system damage or performance problems
resulting from the use of an oxygenated fuel are not the responsibility of Honda and are not
cover under warranty.
Oxygenated fuels can damage paint and plastic. Be careful not
to spill fuel when filling your fuel tank. Damage caused by spilled fuel is not
covered under warranty.
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