Engine Overheating - Johnson 2 Stroke 40 HORSEPOWER Operator's Manual

ENGINE OVERHEATING

IMPORTANT: Do not run your engine — even for a
brief start-up — without supplying water to it. Refer
to Flushing.
While boating, the engine's water intakes must stay
completely submerged and unobstructed. Observe
proper transom height and trim angle. While the en-
gine is running, the engine's water pump indicator
must discharge a steady stream of water. Check
the indicator often, especially when operating in
weeds, muddy and debris-laden water, at extreme
trim angles, or in shallow-water drive (if equipped).
1. Water intake screens
2. Water pump indicator
If the engine overheats, the S.L.O.W. (Speed Limit-
ing Overheat Warning) protection system will im-
mediately limit the engine speed to 2000 RPM. If
the engine was running faster than 2000 RPM
when the S.L.O.W. system activated, it will shake
noticeably.
To RESET the S.L.O.W. protection system, the en-
gine must be shut OFF and the cooling temperature
restored.
IF the S.L.O.W. protection system activates and the
stream from the water pump indicator becomes in-
termittent or stops, reduce speed to idle and:
• Shift to NEUTRAL;
• SHUT OFF the engine;
• Tilt the motor up;
• Clean the intake screens of any blockage;
• Clean the water pump indicator of any blockage;
• Lower the motor; and
• Restart the engine and run at idle.
IF cleaning the screens and indicator does not re-
store the water pump indicator's steady discharge,
SHUT OFF the engine and do not attempt to oper-
ate it. See your Dealer.
IF cleaning the screens and indicator does restore
the water pump indicator's steady discharge, you
might have to run for two minutes in NEUTRAL to
allow the engine to cool.
IMPORTANT: You must restore cooling to the en-
gine to avoid serious engine damage.
After any overheat, have your Dealer:
Torque the cylinder head screws.
Inspect the water pump for excessive wear or dam-
age.
Inspect the thermostats.
Inspect the engine for leaks.
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Operation -