1997 Johnson 50HP Oil Injection

I purchased a 1997 Johnson 50HP, Oil Injection. Ran great the first few times. Then an issue developed at about 3500 RPM, engine started acting up running very rough, shaking. Shutdown to idle and it stopped, put it drive again and it ran rough. Shut it down, then restarted. Ran fine up to the 3300-3500 rpm and the rough running started again. I did hear the low oil level warning go off. Oil tank was nearly full. Shut the engine down again, started up and kept the RPMS low and go home without issue. Started up motor today and the warning went off and engine was acting up in neutral very rough as above. I checked the oil tank, took out the float, nothing unusual. disconnected the oil line at engine there appears to be oil flow. I did note the squeeze bulb was pretty hard. Any thoughts on what the issue might be? Thanks for the help!
David

Re: 1997 Johnson 50HP Oil Injection

I have an evinrude 40 that had oil injection. It had been sitting for a couple of years so I opted to remove the system. I was scared it would fail at some point and my motor would be toast. Changed the fuel pump, and now I mix the gas. Like I said, I think my system was working, I just disabled it for piece of mind. Hope you get it running right.

Brent

Re: 1997 Johnson 50HP Oil Injection

That motor should have the low oil and no oil alarms. Which alarm did you get? Recommend you run premix until you get it sorted out. Rough running is not usually associated with low oil, but you need to find out for sure. If the motor runs OK with the premix, then maybe it is the injection pump. Post back on findings.

Re: 1997 Johnson 50HP Oil Injection

You could check the vacuum pulse hose that goes from the front (closest to the air intake) of the VRO pump to the bottom of the engine block. If that vacuum connection is not closed due to old crusty hose or a hose/hose clamp has vibrated or been bumped lose, then the pump can't "suck" enough oil and gas to the carbs and then the downstream flow to the engine.

Lower than needed oil at at any rpm will cause higher engine temps and the alarm goes off and lower than needed gas at any rpm will cause a rough running engine. So, in your situation, maybe at the low rpm the pulse vacuum is strong enough to pull in the gas and oil through the lines to the pump, carbs and engine but at the +3000 rpm the vacuum pulse it to weak to pull the correct amounts of oil and gas to the carbs and engine.

If you run the premix 50:1 gas/oil and then run it up to 3000 rpm and have a person squeeze the priming bulb? I wonder if you could get higher rpm and avoid a hot engine. If you can push enough gas/oil mix to the engine without any rough spots or alarms you may have a bad VRO pump or vacuum link. Other folks on here will give you great advice on checking compression to make sure you have the vacuum pulling capabilities to pull enough fuel and oil. That is a bit beyond me so I will reserve those comments to those to know better. Hope it works out for you soon.

Here is a shot of the vacuum hose and connection on my 1989 Evinrude 50.
Where the hose connected to the front of the VRO pump.

Engine block location

Re: 1997 Johnson 50HP Oil Injection

Thank you very much! I will use these valuable suggestions.