Honda FourTrax Rancher TRX420FE1 2019 Owner's Manual page 216

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
hot.
POSSIBLE CAUSE
poor or inadequate
fuel flow due to
clogged fuel filter
206 Taking Care of the Unexpected
WHAT TO DO
Check the coolant
temperature gauge and high
coolant temperature indicator.
Refer to If the High Coolant
Temperature Indicator Lights,
page 214.
See your dealer.
See your dealer.
See your dealer.
If applicable, switch to the
recommended octane gasoline
(page 117) 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)