Loss of fuel pressure and "No Oil" alarm - Common cause?

Hello,

Just bought a cottage that came with a 20' pontoon with a 1999 Johnson 50HP oil-injected 2-cycle outboard. It starts great, but after running for about two minutes, the "No Oil" light and alarm goes off, and thirty seconds after that, the engine sputters and dies. At this point, the fuel line has lost all pressure. The engine can be kept running indefinitely by manually keeping the fuel line pressurized, but the "No Oil" alarm remains triggered. I have changed the pressurization bulbs on both the fuel and oil lines.

If the fuel pump is the culprit, would this also cause the "No Oil" alarm? If not, any other ideas would be greatly appreciated.

Thanks in advance!

Re: Loss of fuel pressure and "No Oil" alarm - Common cause?

klschauf said:

Hello,

Just bought a cottage that came with a 20' pontoon with a 1999 Johnson 50HP oil-injected 2-cycle outboard. It starts great, but after running for about two minutes, the "No Oil" light and alarm goes off, and thirty seconds after that, the engine sputters and dies. At this point, the fuel line has lost all pressure. The engine can be kept running indefinitely by manually keeping the fuel line pressurized, but the "No Oil" alarm remains triggered. I have changed the pressurization bulbs on both the fuel and oil lines.

If the fuel pump is the culprit, would this also cause the "No Oil" alarm? If not, any other ideas would be greatly appreciated.

Thanks in advance!

Click to expand...

Intersting! Another guy posted a very similar problem just recently: http://forums.iboats.com/showthread.php?p=2918871#post2918871

You should keep your eye on that thread. I made a suggestion, but I'm not a real pro and hopefully someone else will chime in w/ good suggestions.

My suggestion from that thread:

Here's how the VRO/OMS pump works: http://continuouswave.com/whaler/reference/VRO.html

It sounds to me like both parts of your fuel pump are not working right. The fuel part because you have to pump the bulb to keep it running and the oil part because you get the No Oil alarm. Therefore, my WAG is that either the air motor (which drives both parts of the pump) is failing OR, the pulse that drives the air motor is not adequate.

If it's the air motor, you'll need to get a new pump because I don't know if it's rebuildable.

If its the pulse, first thing I wonder is which cylinder drives the pulse and if that cylinder is putting out enough compression.

Second, of course check all the pulse connections way back to the pulse limiter which is threaded into the crankcase. Of course check all the other fuel and oil hoses and connections too.