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Discussion Starter · #1 ·
So with my recent season ending motor injury plus Skip's unfortunate situation, it got me to thinking about whether I should unhook my VROs and run premix in both of my engines. I recently had a cylinder get scored in my port engine, probably not due to a VRO problem but it got me thinking. I've heard opinions all over the place on this issue but wanted to see what you guys think. I have the updated units on both of my engines, but there's just that peace of mind knowing that both your engines are getting enough oil when you premix. I don't burn a ton of fuel, so the actual task of doing it probably wouldn't be an issue.

Thanks
Chris
 

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Lets see if this makes sense. I was thinking of doing this on my 04 175 Johnson. It was explained to me from several sources that with this E-10 gas possible putting water in your tank and you get a slug of it to your engine, you would have no lube without the VRO. Made sense to me so I left mine hooked up. George
 

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OPTIONS

I did it to my 88 60hp and it has ran great. they have to put a pump dummy plate on it - then you just have to pre-mix fuel. no problem. what it does do is removes one mechanical part that can break and leave you stranded or blown up. The best thing I did to my OMC though to make it run really great and clean is to use mercury premium oil or even better premium plus oil.
 

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Lets see if this makes sense. I was thinking of doing this on my 04 175 Johnson. It was explained to me from several sources that with this E-10 gas possible putting water in your tank and you get a slug of it to your engine, you would have no lube without the VRO. Made sense to me so I left mine hooked up. George
Water and oil don't mix. If you have water in your fuel a VRO isn't going to anything for you.

Having said that, here is a good write up on the VRO system.

The myth of the mixer

continuousWave: Whaler: Reference: VRO Fuel-Oil Mixing
 

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Been running VRO motors for quite some time with the updated pumps without problems. One of my motors is on an old river racer that I spin up to 7000rpm ! I use premium oils and a minimum 89 octane fuel. 87 octane in the older two strokes will cause piston failures. 87 octane E 10 gas will burn'em up.
 

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Discussion Starter · #6 ·
I guess the other thing I'm considering is problems associated with having the VRO that might not necessarily be due to the pump. By this I mean junk/condensation in the oil tank, an air leak in a hose somewhere under the deck where you can't see it, etc that can all lead to a blown engine. I haven't had any problems with mine as far as I can tell, as a single cylinder having a problem wouldn't be due to a VRO (as I understand it all cylinders would go as they all get the same gas/oil mix out of the VRO), but my recent experiences just got me pondering this topic.
 

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I guess the other thing I'm considering is problems associated with having the VRO that might not necessarily be due to the pump. By this I mean junk/condensation in the oil tank, an air leak in a hose somewhere under the deck where you can't see it, etc that can all lead to a blown engine. I haven't had any problems with mine as far as I can tell, as a single cylinder having a problem wouldn't be due to a VRO (as I understand it all cylinders would go as they all get the same gas/oil mix out of the VRO), but my recent experiences just got me pondering this topic.
If you have a leak in either the fuel or oil line you'll get an alarm from the VRO. On a VRO a leaking or restricted fuel line will cause you to over oil and possibly foul the plugs.

What happens if you pre-mix and have a leaking fuel line or forget to add oil when you fuel up?
 

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Discussion Starter · #8 ·
A leaking fuel line isn't so much what I'm worried about as I am a leaking oil line. I'd say, for arguments sake take the "it's a pain to mix oil" or "you could forget to mix oil" arguments out of the question for now, as I am pretty confident I'm competant enough to mix 50:1 oil. Are there any real *disadvantages* to unhooking the VRO beyond convenience? I know there are alarms on the pumps, but what happens when the alarm fails?
 

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If you remove the VRO..Like in the old Pasta Commercial...It's in there...
 

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You loose the fuel restriction alarm.......acts as a lean alarm. The lean alarm on a pre-mix is Ka..boom.

"It's in there" isn't going to do you any good if it's not getting to the right place at the right time.
 

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If it was the #1 cylinder, it could also be a bad upper crank seal allowing air get sucked into the #1 crank case section causing a lean condition. What octane fuel have you been using ?
 

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Discussion Starter · #13 ·
I'm actually pretty sure in my case it is a stuck rear ring, my VRO question wasn't really related to my engine problem in the sense that it was the cause. I don't think it could have been. I've been using 87 as that was what several mechanics told me this engine was designed to run. Perhaps I should start using 89? I also run racor 10 micron filters on both engines to combat the ethenol issue with no junk or water in the bowls to date.
 

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Stuck ring will do it for sure. I treat my motors with Yamaha Ring Free. What year is your motor? If it is mid 80's to early 90's, you should run 89. Most of the gas docks sell 89. Some of the older loop charged OMC's can run 87. I run my stuff hard so I always go with the 89.
 

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Mike, why would switching to a higher octane rating help if the motor is designed to run on 87?
 

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Discussion Starter · #16 ·
Mine are both 91 Johnson 120 loop charged engines. I always decarboned them every season (low hours, but still did it) and they had low hours on them when I bought them. Oh well, guess it happens. The cylinder/piston aren't completely toast (about 80lbs vs 135), but you can see the scoring. My mechanic who's been working on OMCs for 30 years said he's almost positive it's a stuck rear ring.

So if I'm getting this right from everyone:

Disconnecting VRO has the following:

Pros:
- You know you're getting 50:1 barring any fuel restrictions (and that you remembered to put oil in the tank)
- You don't have to worry about the VRO pump failing and not getting an alarm (or getting it too late)
- You don't have to worry about water or junk in your oil tanks
- You don't have to worry about a leaky oil hose sucking in air

Cons:
- A fuel line restriction could cause your engine to run lean, causing damage
- It will probably smoke a bit more and use a bit more oil
- Carbon buildup (not likely an issue for me, I don't put a lot of hours on them and I decarbon every year)
- Gotta remember to mix oil

Anything I'm missing?
 

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Unless the factory put it in writing, I would not use 89 octane fuel on a motor designed to use 87 octane. 89 octane is not more powerful than 87 octane! Save the difference in cost between the octanes and put that savings towards SeaFoam or an other brand of carbon removal agent. It's money well spent!

As for the VRO:
Water can also get into the oil reservoir. That's what happened to mine causing water to be mixed with the gas resulting in scored cylinder walls necessating a rebuild. The VRO was then disconnected. The motor is now on it's third hull running as good as new. It's a 1985 Johnson 70 HP. It gets a Seafoam shock treatment regularly (every 50 to 75 hours) and has a couple ounces of SeaFoam added to the gas/oil mix every time I fill the gas tanks.

It's disheartening when a 50 cent gasket on an oil reservoir leaks and allows rain to enter the reservoir. You never know it's there until it's too late! VRO pumping systems cannot differentiate between water and oil. The water settles to the bottom of the reservoir and gets pumped out first followed by an expensive rebuild in most cases.

IMHO I would remove the VRO system and return to the way we treated gas in the past before these labor saving gadgets that cost us more $$$ initially and even more $$$$ later when they malfunction.

Good luck with your decision.:thumbup:
 

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Discussion Starter · #18 ·
Thanks Polecat. I think I'm leaning towards disconnecting, as I see only 1 potential pitfall (the fuel line restriction) vs several (water/junk in oil tank, oil line leak, faulty vro pump, faulty warning alarm. Another thing I've learned, commercial versions of this engine came with a straight fuel pump, no VRO. If it's good enough for someone beating their engine to death on a daily basis, it's probably good enough for me.

Plus, I figure if I can't remember to put oil in or mix it properly, I probably shouldn't be operating a boat.
 

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Took My VRO OFF

My VRO is disconnected on a 1993 200 HP. on the advice of a master OMC technician, Francis Guy, Guy Bros. Marine. He stated that it just wasn't worth taking the chance of the existing pump or paying $250-$300 for a new pump.

Carbon Guard in every gallon of gas I burn, Sea Foam de-carbon once a year.
 
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