How to Install Johnson Boat Motor Water Pressure Gauge

Johnson outboard motors use a vane-type impeller water pump to supply cooling water for the engine. The pump is a positive displacement pump that moves high volumes of water at low to medium pressure. The pump pressurizes the engine water jacket, where water flows around in the block and the cylinder heads, carrying off heat. Every engine comes equipped with a water flow indicator that shoots a small stream of water out of the engine that is visible to the driver. This indicates that there is some pressure, but not how much. Only a water-pressure gauge can indicate the water-pressure in the motor.

Things You'll Need

• Hole saw
• Drill motor
• Allen wrench set
• Adjustable wrench

Instructions

1. Locate a safe place to mount the gauge in the dash. Pick a spot with no wires or hydraulic lines under it.

2. Bore a hole in the dash with a hole saw and drill motor. Size the hole saw so there is minimum clearance between the dash and the gauge.

3. Install the gauge in the hole. Clamp the gauge in place with the methods supplied by the gauge's manufacturer.

4. Locate the water pressure tap in the engine block. The tap plug will be an Allen screw located near the bottom rear of the block on the right side. Remove the plug with an Allen wrench.

5. Install the water pressure gauge tubing into the water tap, then tighten the nut with an adjustable wrench. Lead the gauge tubing up to the gauge. Screw the tubing into the gauge, then tighten the nut firmly with a wrench.

References

• TJ Hinton; commercial fishing vessel captain; Gulf Coast, Mississippi