Evinrude E-NATION, for those dedicated to water, power, fishing and fun
Posts: 2
Registered: ‎02-18-2012

150 johnson outboard

 Is it ok to bypass oil injection and just mix my gas

Posts: 9,047
Registered: ‎07-14-2011

Re: 150 johnson outboard

[ Edited ]

The oil metering system (OMS), often mistakenly called VRO, is easily bypassed and that is explained in your owners manual.


First make sure that a 50:1 fuel-oil mix is already in gas tank and the motor has been run to get the pre-mixed fuel into the engine before the bypass operation is completed.


Remove the oil line at the pump and cap off the fitting to keep water, dirt, and bugs from getting into the pump. Plug or remove the oil line from the motor. Trace the wires from the oil tank and disconnect them at the motor to disable the LOW OIL warning components. Then unplug and protect the 3 or 4 wire connector from the "VRO" to disable the NO OIL warning system.


The "VRO" is also the fuel pump so that has to be in operational order and provide enough fuel flow and pressure for the engine to run correctly. Evinrude does make a pump conversion that is a fuel pump only, but the cost is almost as much as the complete oil metering system assembly.


Be aware that the gas has to have oil added at each fill-up. Many more engines are damaged from people forgetting to add oil after the oi pump was disconnected than were ever damaged by a faulty pump.


Follow this link to learn more about the oil metering system:






"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 



The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.