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disabeling VRO on evinrude 1989 40

G

glenn_1

Member
hi guys, i just picked up a cheap boat with a 1989 evinrude 40 with VRO. i have always mixed my gas for all my previous engines but i am not familiar with the VRO system and was advised by several boater friends to disconnect the VRO and mix my gas before the system fails and i cook my motor. what do i have to do? i know there are several sensors and alarms hooked to it.
thanks
 
Re: disabeling VRO on evinrude 40

Disconnect the oil line on the VRO pump and securely cap the nipple, then follow your wires back to the low oil alarm and disconnect them. I never did like the older VRO that OMC manufactured. I have heard several stories about them and have seen a couple of results of a failed VRO pump.
 
Re: disabeling VRO on evinrude 40

First, If disabling the VRO is what you need to do to be comfortable then go for it.

Before you decide though, search the forums. I don't think you'll find a single first hand account of a failure of the oil side of the VRO toasting a motor. The only powerhead failure from a VRO that I can recall on this forum comes from a failure to deliver enough fuel thus leaning out the mix. This failure can occur with any fuel pump. You'l find lot of "my brother in-law's cousin's wife's sister's dad's neighbor's motor blew up because the VRO went bad" In reality they work pretty good, are alarmed better than any competitive model, and failures rarely involve the oil side of the pump.

Now, if you search the forums again, you will find at least two instances of powerhead failures because of failing to mix the fuel properly.

It's your choice-take your pick!
 
Re: disabeling VRO on evinrude 40

Just to reiterate, I've premixed and used the VRO/OMS system and prefer the VRO/OMS. I firmly believe that - for me - it is safer to maintain and monitor a VRO/OMS system than to pre-mix in my built in tanks. And I've been a pre-mixer since I was a kid in the 60s, so it's not like I"m unfamiliar with the process, calculations, etc. It's just easier for me to top off the oil tank (mine is quite visible, not to be forgotten!) than to figure out how much gas will be going into my tanks, measuring out the oil, mixing them through the funnel, etc.... but remembering if I've done it or not and/or supervising family or other helpers to do it right.

But opinions go both ways. Read this before you decide:

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

But disconnecting is very easy. Just to flesh out what cubonfloats wrote above:

While you're still running the oil mixing pump, run premix gas to flush the raw gas out of carb bowls, fuel lines, filters, etc.

Cut oil line near the fuel pump, plug with a bolt and hose clamp. Make sure there's absolutely no air leaks. I personally recommend this rather than disconnecting the oil line and covering the nipple with a cap. I had a pump that was d/c'd that way and the rubber cap degenerated (rotted, cracked) and leaked air. The air leak caused performance problems, and can damage the engine due to lean fuel and resulting lean lubrication. I think the original oil hose, plugged close by with a bolt and clamp is just easier and better.

Unplug the wire harness from the fuel pump (will have 3 or 4 pins, probably 4).

Remove tank and disconnect wires running from tank to engine.

Tape and/or secure the loose wires and plugs in engine compartment so there's no chance of shorting.
 
Re: disabeling VRO on evinrude 40

I know some of the Suzuki's from back in the eighties had an oil pump that injected oil into the intake manifold before the reeds. That oil mixed with the fuel that was drawn in through the carb and was burned like a premix. The oil pump was mechanical, no electronics to meter oil flow so that if the carbs were gummed from sitting and leaned the fuel, the oil mix would not change and save the internal parts even though the engine would still run in a lousy lean state.
I have seen two 120's that were determined to have had VRO failure, so it does happen and if yours is an older version, there is nothing wrong with disconnecting it and using a premix. It takes all the worry out of weather or not it is working good while you're at WOT.
The dealership I dealt with would not warrantee a rebuild if the owner did not put a new VRO on the engine, or only use the existing VRO as a pump for pre mixed fuel. I am sure the ones today are better designed , but in the 80's & 90's there were some problems.
 
Re: disabeling VRO on evinrude 40

thanks guys, i managed to find another fuel pump to replace the VRO pump and i am going to install it and start premixing the gas.

Cheers to all
 
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