VRO Question this may sound stupid

I have a 1977 115 Evinrude VRO<br />I understand the VRO means Vaurable Ratio Oil system. But I also understand that to mean oil injected. I know that the oil injection system was not produced on motors after 1983 or so. So what does VRO stand for on motors produced before 1983 or so. I understand that the oil injection system is made to distribute oil evenly between all cylinder which I guess is beter than just mixing n the gas tank.<br /><br />So am I way off in my understanding. <br /><br />So I guess my question in the end is what does VRO stand for when there is no oil injection system on the motor and how does it work any different than a motor that is not a VRO and gas is mixed in the tank.

Re: VRO Question this may sound stupid

I think you have your wires crossed. VRO didn't come out until sometime in the mid 1980s, Can't remember the exact year. Before that you had to mix your oil and gas. You can't have a 1977 115 Evinrude VRO because they didn't exist yet. 1987 I'd believe. VRO stands for Variable Ratio which it was at first, but the first generation VROs didn't fare too well and the subsequent models mix at a fixed rate inside the pump. Is it possible that somebody but a newer hood on your motor that has VRO on the sticker?

Re: VRO Question this may sound stupid

Hey Guys,<br />This is what the Official Clymer shop manual says:<br />The OMC Economixer is an electronically controlled oil injection system that can be installed as an option on all 1980-1983 V4 and V6 models. Variable ratio oiling (VRO) is a factory-installed automatic oil injection system on 1984 and later V4 and V6 models and 1985 2 and 3 cylinder models.<br />I'm glad we got that cleared up.

Re: VRO Question this may sound stupid

econmixer is dead!! VRO started in 1984 v4 v6 <br />please post your modle number to determine modle year Willey is correct all new Vro pumps are now fixed ratio at approx 50:1 they are now called oms pumps (oil mixing system) and referred to as oil injection

Re: VRO Question this may sound stupid

The OMS pumps came out in about 1992 and they are NOT a fixed ratio. They have a limited range depending on rpm and throttle opening. At idle they are about 75:1 and at WOT it is 50:1. Most recreational users will see a 60:1 average during normal operations.

Re: VRO Question this may sound stupid

Can the OMC Economixer Fuel - Oil Ratio be set or changed?

Re: VRO Question this may sound stupid

Now you know why, we do not recommend Clymer manuals. none of the motors are "oil injected", it is an oil mixing system. VRO, VRO2 and OMS. they just mix oil with the gas, before it reaches the carbs.