Honda FourTrax Foreman Rubicon TRX520FM6 2020 Owner's Manual page 220

If Your Engine Quits or Won't
Start
SYMPTOM: Engine starts, but runs poorly.
POSSIBLE CAUSE
high coolant
temperature
runs erratically, misfires
blubbers (rich fuel
mixture)
sooty exhaust (rich fuel
mixture)
detonates or pings
under load
afterfires (backfires)
pre-ignition (runs on
after ignition switched
OFF)
SYMPTOM: Engine starts, but runs poorly or dies when
POSSIBLE CAUSE
poor or inadequate
fuel flow due to
clogged fuel filter
210 Taking Care of the Unexpected
hot.
WHAT TO DO
Check the coolant
temperature gauge and high
coolant temperature indicator.
Refer to If the High Coolant
Temperature Indicator Lights,
page 215.
See your dealer.
See your dealer.
See your dealer.
If applicable, switch to the
recommended octane gasoline
(page 126) or change your
brand of gasoline. If the
problem persists, see your
dealer.
See your dealer.
See your dealer.
WHAT TO DO
See your dealer.
(ensure clean fuel supply)