Evinrude VRO Experience -anyone else see this?

[Digdug]

1994 Evinrude 225 with VRO. Motor has not been run for several months. Decided to drain fuel tank and replace with fresh gas before starting. Disconnected fuel line at the inline filter (just before fuel pump) and started pumping bulb to drain tank. Instead of gas I got what looked like pure 2 stroke oil (no I did not disconnect the oil line). After several pumps the oil was gone and gas began coming out. I visited local marine dealer and the mechanic said that he had seen this many times this spring. Mechanic said the check valve in VRO goes bad and the 2 cycle oil will drain back down the fuel line. People will pump bulb and fill carbs with 2 stroke oil. Then engine will not start or will be very hard to start. Mechanic claims most of the engines with this problem are around same year model as mine (1994). Mechanic said he has replaced several VRO's this year because of this problem. I have since disconnected the VRO and mix gas in tank. <br /><br />Has anyone else seen this? This could explain why some engines smoke a lot at first start up?

 

[clanton]

Re: Evinrude VRO Experience -anyone else see this?

Check valve is my guess, I see this, and the ones that have been running premix, if you remove the cap/plug from the pump oil intake, run engine 1500 rpms gas will dribble out of the pump. Sometimes gas will drain back to the oil tank. The first one I seen this on was 1986 GT150 with VRO2 upgrade.

 

[jegervais]

Re: Evinrude VRO Experience -anyone else see this?

Actually guys, if you think about the internal design of the pump and where the check valves are located, it's not the check valve that allows oil into the fuel, it's the oil piston seal. It's correct that the fuel check valve isn't doing its job either...<br /><br />I have also seen a few pumps do this.<br /><br />-John

 

[Digdug]

Re: Evinrude VRO Experience -anyone else see this?

John/Clanton, I am not familiar with the internal design of the oil/fuel pump. Could this condition (improper oil piston seal and faulty check valve) cause engine failure due to improper lubrication? Clanton states gas can actually drain back into oil tank causing oil in tank and oil line to be diluted. Sounds like this could be a serious problem if gone undetected?

 

[jegervais]

Re: Evinrude VRO Experience -anyone else see this?

If you have oil getting into the fuel system, it'll only create hard starting problems or cause the motor to smoke excessively. If you've got fuel getting into the oil, then it can damage the powerhead. I've never personally seen fuel in the oil.<br /><br />-John

 

[seahorse5]

Re: Evinrude VRO Experience -anyone else see this?

Pressure buildup in the remote oil tank can give the same symptoms. The cap is vented for vacuum but not pressure. You can keep the cap loose on the tank if it is in a protected area, or some folks use a paper clip to push thru the rubber membrane to vent it both ways. If you have the cap with the clear plastic top with a black "button", replace it with the newer all black cap.

 

[62_Kiwi]

Re: Evinrude VRO Experience -anyone else see this?

Seahorse - what would cause a pressure build up in the oil tank ? I can understand vacuum due to the extracted oil - but how would it get pressure ?<br /><br />I'm interested in this topic, because about 1 time in every 10, my oil injected Evinrude is very difficult to start from cold and after being difficult to start, when it does, it acts like the motor is full of oil - lots of very thick smoke. After reading this thread, I'll get the VRO checked as well as checking for pressure in the oil tank.

 

[clanton]

Re: Evinrude VRO Experience -anyone else see this?

Heat, A GradyWhite with twin 150 johnson, that I maintain for a friend has one engine that will push oil back thru the fuel line to the remote filter in 3/4 days in the summer. The remote filter is about 6 feet from the VRO pump. Probley replace pumps on both engines soon.

 

[seahorse5]

Re: Evinrude VRO Experience -anyone else see this?

62_Kiwi,<br /><br />Temperature changes build up pressure. Just like in a sealed gas tank, more heat, more pressure.<br /><br />If you take apart and inspect the oil pump section of the pump assembly, there is very little volume of oil in the cavity. Something has to push more oil into the pump to fill the fuel chamber and the carbs with oil. If oil is backfeeding thru the inlet line, then the fuel inlet check valve is leaky and the pump should be replaced. The newer pumps that have the fuel outlet fitting held in place with an oval metal plate and 2 Torx screws are rebuildable.

 

[62_Kiwi]

Re: Evinrude VRO Experience -anyone else see this?

Many thanks to Seahorse and the others on this thread. What you're saying makes sense and might be the answer for the sporadic problems I've been having. In my case, I suspect that heat on the oil tank is the more likely of the two causes (but I'll check for both).