Gone Outdoors

How to Troubleshoot a Johnson Outboard VRO System

by Will Charpentier

Troubleshooting the Johnson Variable Ratio Oil system is a three-pronged attack. First, you must determine whether or not the System Check system is registering a problem. Then you have to test the reservoir level relay and the float attached to it, to ensure they're operational. Finally, you must ensure that the system will detect an interruption of the variable oil mix ratio. Three tests and solutions for each problem mean a busy afternoon of maintenance.

Drain oil from the motor's oil reservoir into a container suitable for the storage of oil until there is less than 1/4 of the reservoir's capacity left. Turn the ignition switch on. Wait for the Johnson System Check gauge to complete the self-test and watch for the "Low Oil" warning to illuminate and the warning horn to sound.

Add oil to the oil tank slowly. As you do so, the "Low Oil" warning light should go out and the audible warning should stop when the float in the tank passes the "1/4 tank" level. If it does not, drain the reservoir into a suitable container and clear away any debris that may be jamming the float. If the float moves freely, replace the relay and the float. If the problem persists, check for loose wiring from the float relay to the System Check panel and the LED. Tighten connections if necessary, or replace the LED if all else is in order.

Disconnect the oil and fuel lines from the outboard. Connect a portable tank containing a 50-to-1 fuel/oil mixture to the engine's fuel inlet line. Start the motor and run the outboard at 1,500 rpm. The "No Oil" System Check LED should illuminate if the system is working correctly. If the "No Oil" warning doesn't light, replace the LED and repeat the test.

Items you will need
  • Suitable container for oil
  • Oil reservoir float and relay
  • LED
  • Portable fuel tank
  • 50-to-1 gasoline-to-oil mixture


  • "Johnson Repair Manual 2.5 to 250 HP Models, 2002-2007"; Seloc Marine; 2007

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