Vary pump v.s. Fixed pump VRO

[thestoops]

It is my understanding that the stock VRO on my 1987 Evinrude 140 v4 outboard has a VRO that delivers from 50:1 to 150:1 depending on throttle<br />position. I am looking to replace my VRO and I am hearing that the new VRO's are fixed at 50:1 no matter where the throttle is.<br /><br />Why did they change this and what is the advantage?<br /><br />Thanks,<br />Fisherman

 

[DJ]

Re: Vary pump v.s. Fixed pump VRO

Fisherman,<br /><br />The new pumps also included a better warning system.<br /><br />I don't believe there was a real issue with the true VRO other than the warning system was somewhat lacking.<br /><br />You can convert, very easily.

 

[thestoops]

Re: Vary pump v.s. Fixed pump VRO

what was the improvment in the warning system?

 

[DJ]

Re: Vary pump v.s. Fixed pump VRO

I believe the newer systems could detect low oil and a fuel/oil restriction. I'm a little fuzzy on this one.<br /><br />I believe they were changed about 1989.

 

[clanton]

Re: Vary pump v.s. Fixed pump VRO

The early pumps did not have a no oil being pumped<br />sensor. Sometime in 1989 OMC made the VRO2 avalable to all orginal engine owners in kit form for 69.95, owner paid labor. This kit included new pump with 3 wire warning sensor (I think) all new hoses, new nipple for block, and a change in diphram material. The very first VRO systems had a sponge like material for a filter in the remote tank, some oils melted this filter, service letter from OMC to change this to new style sock filter at 20 hour service. Most probley never got changed.

 

[seahorse5]

Re: Vary pump v.s. Fixed pump VRO

Clanton is right about most of the changes. It was in '86 that the alarm system came into being and could be retrofitted back to '84.<br /><br />The current pump since 1992 is actually called an oil metering system, OMS pump. It only varies from 75:1 at idle to 50:1 wide open. On average use, you will see about a 60:1 ratio.

 

[Cricket Too]

Re: Vary pump v.s. Fixed pump VRO

seahorse...Is that sock filter, that clanton spoke of, still on the new OMS pumps? And if so how do you go about changing them?

 

[seahorse5]

Re: Vary pump v.s. Fixed pump VRO

Originally, in 84, there was a small cone shaped screen that would plug up with gelled oil, before the days of TC-W3. Then they added a foam collar around the oil pickup to keep that from happening. Finally a year or two later, someone got smart and designed a long "teabag" style filter screen that is still used today. Just remove the pickup assembly, pull off the old screen and push on the new one, making sure it points in the same direction as the old one.

 

[Melvin Hatcher]

Re: Vary pump v.s. Fixed pump VRO

Another small cone shaped screen is in the oil hose that attach to the VRO pump. I removed mine after getting a no oil signal, and it was not plugged or dirty. I removed it and no more no oil signal.