Is an '89 VRO rebuildable?

[Lowranger]

My 1989 Johnson 70 is running the original pump and I've been advised by a respected OMC Tech to either disable oiling(preferred) or replace it with a new pump(O.M.S.?). I understand that MY pump runs less oil @ idle and that a new one simply runs 50:1 all the time. I've read that Joe Reeves thinks the design was perfected around 1988. I run my motor @ or near idle speed when ocean trolling for salmon and believe the leaner ratio helps reduce smoking/fouling/rough idling. Is my older pump re-buildable? Do I need a new pulse limiter? If new pumps ARE 50:1 then it will be hard for me to justify the $270.00 simply for the convenience of not pre-mixing. Finally, my fuel tanks are built-in 18s that complicate getting a perfect 50:1 ratio due to the uncertain fuel level remaining in the tanks. Should this affect my decision?

 

[seahorse5]

Re: Is an '89 VRO rebuildable?

The "VRO" was redesigned in 1992, then again in '98. The '92 and later pump was called an oil metering system (OMS) and for some reason, folks think it only pumps 50:1. Actually is is a closer range variable pump from about 75:1 at idle and 50:1 at high speeds. A recreational boater averages about 60:1 with that pump.<br /><br />Tha latest pumps with a 500.... part number are the best, but they are $270. They come with a new pulse limiter and needed fittings and wiring harness.<br /><br />You are on borrowed time on that 16 year old VRO pump with its unreliable 3-wire alarm system. <br /><br />Read this forum's FAQ section, part F., for more info on the VRO and how it works.

 

[seahorse5]

Re: Is an '89 VRO rebuildable?

I forgot to add, the only rebuildable part in your original pump is the fuel pump diaphragm. Your parts person has to look it up under a 1998 or later parts book.

 

[Lowranger]

Re: Is an '89 VRO rebuildable?

Thanks for the reply Seahorse, If I disconnect the VRO and premix, will extended idle speed operation(trolling) still be possible? How about smoking/fouling/rough idling?

 

[DHPMARINE]

Re: Is an '89 VRO rebuildable?

lowranger,for extended trolling (hours and several lines out) renew your VRO pump.If you premix,and have lots of line out,the motor may stutter,the lines go slack.....<br /><br />DHP

 

[Lowranger]

Re: Is an '89 VRO rebuildable?

DHP, Thanks for the reply, I just read this posting from OB <br />Rear Admiral <br />Member # 15076 <br /><br /> posted December 08, 2004 06:14 PM <br />--------------------------------------------------------------------------------<br />"unless your old vro was kaput,the earlier year vro pump varied the ratio for you.The later ones deliver 50:1 regardles of rpms". Yet Seahorse says, "The '92 and later pump was called an oil metering system (OMS) and for some reason, folks think it only pumps 50:1. Actually is is a closer range variable pump from about 75:1 at idle and 50:1 at high speeds." I'm now TOTALLY confused. I do'nt know if the new VRO pumps vary the ratio or not. If the new VRO pumps do'nt vary the ratio than I do'nt think I can justify the $270.00. Can anyone out there settle this?

 

[seahorse5]

Re: Is an '89 VRO rebuildable?

The oil ratio varies with the newer style pumps.<br /><br />Read the FAQ forum, section F, the VRO story, in this newsgroup.

 

[ob]

Re: Is an '89 VRO rebuildable?

seahorse is likely correct.There is a lot of mixed info on the later vro pump ratio.A local dealer mech told me it ws straight 50:1 on the later vros but I have seen no consumer John/Rude literature that stated such.If seahorse says 75:1 at slower speeds and 50:1 at higher,that's good enough for me.Heck,mine's bypassed any hoot.

 

[Lowranger]

Re: Is an '89 VRO rebuildable?

Thanks to seahorse, DHPMARINE, and ob for your replies,

You are on borrowed time on that 16 year old VRO pump with its unreliable 3-wire alarm system.

So, if I upgrade(new VRO) I'll idle @ a 75:1 ratio. If I disable I'll idle @ a 50:1 ratio. That has me burning two or three times as much oil @ idle. Smoking/fouling/rough idling. Is my '89 VRO pump truly a "Time Bomb" waiting to oil-starve my motor? Or is it more likely to fail on the fuel side, causing no damage? 150:1 sure idles and trolls good and has worked perfectly for 15 years.

 

[seahorse5]

Re: Is an '89 VRO rebuildable?

Most likely it will fail to pump enough fuel if the motor backfires a lot during warm up. The 3 wire alarm electronics are not as reliable as the later 4 wire version. Should an air leak develop in the oil line or if the flow is restricted, or if the pump linkage fails, that older alarm may not sound off like it should.

 

[Lowranger]

Re: Is an '89 VRO rebuildable?

OK Fellas, After considering your advice I've decided to upgrade. My OMC manual does'nt address VRO removal/installation. It appears that I should remove the air-silencer cover and then the air-silencer body to access the VRO mounting bolts/hoses. I assume I'll want to replace the cover gasket(cork) and the silencer body/carb gasket(rubber). The manual DOES say that hoses should NOT be pried off the VRO nipples but cut off instead. Is there anything else you think I should know before I proceed? As always, Thanks

 

[seahorse5]

Re: Is an '89 VRO rebuildable?

If you are replacing the pump, go ahead and pry the lines off, what have you got to lose. On that old a motor, you should probably replace any soft or brittle fuel and oil lines while doing your repairs.<br /><br />See your dealer and ask to copy the VRO installaton from a 1998 or later manual. The new pumps also come with an abbreviated installation sheet. Be sure to use the factory clamps, no tyraps or hose clamps on the oil line.

 

[Lowranger]

Re: Is an '89 VRO rebuildable?

Thanks for the help.

 

[piers]

Re: Is an '89 VRO rebuildable?

What are the differences between the 1997 vro and the 1998 version?

 

[seahorse5]

Re: Is an '89 VRO rebuildable?

Originally posted by prawntrap:<br /> What are the differences between the 1997 vro and the 1998 version?

You ought to read the FAQ section, part F., about the history and changes to the VRO pump.

 

[Lowranger]

Re: Is an '89 VRO rebuildable?

Seahorse, I forgot to ask a question concerning the wires on the new pump. The connector on my motor has 3 wires and the new pump will have 4. Where does the 4th wire on the new pigtail connect? In other words, how does a 3-wire plug connect to a 4 wire plug?

 

[seahorse5]

Re: Is an '89 VRO rebuildable?

The correct "VRO" kit includes the harness for the 4th wire and a 4 pin connector. It ties into the purple accessory wire. The instructions explain it for you.