Evenrude 225 Vro Pump Questions.

[jurgenscraft]

i have heard it being said that the " 4 wire " vro pump is the system to have. I have a 2 wire VRO pump, what are the two extra wires for, all I can figure out is that there is a negative wire (ground) and a possative supply wire,
The way I see things is once the ignition switch is turned on and the motor is started ,oil is pumped through to the carburettors and away you go. But it looks like this system has no form of regulation and will pump extra oil at low rpm and the correct mixture at higher rpm, say from 3500 rpm and higher,if this is so then fouling of the spark plugs will occur at low rpm . say trolling just above an idle for a couple of hours,maybe the way to go is eliminate the vro sustem and pre mix at 50:1 and keep a constant oil fuel mixture at all rpm. Am I thinking logically or what? kind regards W8illiam Wright.

 

[rodbolt]

Re: Evenrude 225 Vro Pump Questions.

no logic at all.
50/1 is the output of the 4 wire pump, however the 4 wire pump has more and better alarms and is more reliable than the 2 wire. in fact I wont work on the two wire system unless the customer either updates it or goes to pre-mix.
the 2 wire pumps were not particularly reliable.
the 3 wire was a bit better,4 wire failures are rare yet still get blamed for a lot of failures.

 

[jurgenscraft]

Re: Evenrude 225 Vro Pump Questions.

Ok rodbolt, thanks for the reply, what I was trying to say is " will it not be better to premix the oil and fuel in the tanks at 50:1 "and run the motor like that permanently, thus eliminating the 2 wire VRO failure problem, what are the extra wires on the VRO for any way? thank you once again, Kind Regards William Wright

 

[rodbolt]

Re: Evenrude 225 Vro Pump Questions.

depends on how much your mixing, have seen way mor motors damaged when trying to pre-mix 80+ gallons than all oil pump failures combined.
the 4 wire pump has a tach signal,ground,alarm circuit power and alarm wiring,its also called an Oil Metering Pump now. they say it varies some from 50/1 but not much. some of the early 2 wire pumps were said to go as lean as 150/1 in certain models.
the pump is not expensive and is a maint item occasionally. replace it before it breaks and its cheap.
wqhile VRO got blamed by thousands of poorly trained to non trained personell it was actually rare to see an oil failure after 1985 with the VRO2 setup.
however they do fail, as does most everything else with rubber and moving parts.
I reccomend most my OMC/BRP guys to replace the pump every 6 years or so and clean the oil pickup filter as well as test the low oil and no oil alarms at least yearly.

 

[seahorse5]

Re: Evenrude 225 Vro Pump Questions.

The following link will give you a better insite into the VRO system and how it works, There was never a 2 wire pump. The first ones did not have an alarm, then they had 3 wires and finally 4 wire systems.

http://continuouswave.com/whaler/reference/VRO.html