# Pre-mixing vs. VRO injection



## Play'N Hooky Too (Sep 29, 2007)

My boat, Wellcraft 23 WA w/ 200 Evinrude, as with most, has the VRO injection for the 2 cycle engine oil. I have been advised by my local mechanic that he would recommend disconnecting the oil injection system and premixing. I can see where this might be a safer approach but was looking for some experieinced opinions on this. What brought this up was that I noticed that the motor seemed to smoke more than I would expect for even a 2 cycle engine and ask him if there was any way to adjust the oil injector or to make sure it was providing the correct mixture.

Thanks 

Alan


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## -=Desperado=- (Jun 19, 2009)

> *alanbarck (8/1/2009)*My boat, Wellcraft 23 WA w/ 200 Evinrude, as with most, has the VRO injection for the 2 cycle engine oil. I have been advised by my local mechanic that he would recommend disconnecting the oil injection system and premixing. I can see where this might be a safer approach but was looking for some experieinced opinions on this. What brought this up was that I noticed that the motor seemed to smoke more than I would expect for even a 2 cycle engine and ask him if there was any way to adjust the oil injector or to make sure it was providing the correct mixture.
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i have the suzuki and i asked gary if ineeded to remove it he said hell no.there fool proof.he said there was a part that needed to be replaced on all of them but he told me they are not designed to go bad.this is for suzuki i dont know about yamaha.i would imagine its like anything else it needs to be checked on from time to time but i went with what gary said,.he said from time to time he sees blown motors because of it but it is always because of that part.


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## Play'N Hooky Too (Sep 29, 2007)

I guessmy main concern is the implications if it stopped working for whatever reason. The way my luck has been going lately I'm getting to where I don't trust anything, especially something as critical at that system. Then again, pre-mixing oil into 100 gallons at a time.....


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## welldoya (Oct 5, 2007)

I'm certainly no mechanic but have read threads about this subject on quite a few boating forums. One thread in particular that I remember said that if the VRO goes bad, most of the time it mixes too much oil instead of too little. At least it wouldn't ruin your engine.


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## reefcreature (Oct 3, 2007)

good question! i have been thinking of reconnecting my vro on my johnson. it is a pain to fill the tank (83 gallon) and make sure you have room to mix the proper amount of oil. if you put the oil in then fill it up it may end up with too much oil. then again if you fill it up you may end up putting too much gas in and end up removing some to put the proper amount of oil. fuel gauges are not totaly accurate on the level so it is hard to guess the actual amount that is in the tank.:banghead


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## MirrOman (Dec 25, 2007)

I had the same setup on an early 90's Evinrude, 22 gallon tank and would mix oil in addition to what the VRO would do. She would smoke a little more than usual, and the plugs would foul faster, other than that no noticable difference. I think all 2 strokes are designed to run 50:1, I was trying to be around 30-35:1, more or less to just be cautious.


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## wld1985 (Oct 2, 2007)

I premix my 150 Johnson, it had the VRO on it but last owner took it off.. I like to premix it that way I know nothing is going to happen... When takin the boat out I usually have more then 1/4 of a tank so I'll just throw in 13-15 gallons of new fuel.. You can find charts online to get whatever mix you want..


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## DOUBLE "D" & LV (Oct 2, 2007)

Usually the johnson/evinrude vro system puts too much oil in when they go bad. Sometimes they do the opposite. Keep in mind that adding more oil takes the place of fuel. This in turn runs the fuel air mixture lean and can cause damage to the cylinder walls and pistons. Equate it to a slight restriction in a carb or fuel injector not letting enough fuel in. You may not notice it now that much, but in the long run it will cause the engine to wear faster. If you plan to mix the system, you will save the initial investment of the vro pump, but if the fuel side of the pump is actually bad, then you will need to replace it anyway. If you don't want to mess with premixing, then get the $400 pump and it should last a few more years for you. (unless ethanol kills it)


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## gmblnfool (Jun 10, 2008)

The previous owner disconnected the VRO. He had to rebuild one of the Johnson 150's due to the VRO failing. For me it is not to bad premixing the 150 gallon tank. I don't trust the fuel gauges so I judge by mileage approx how much fuel I need and then make sure I need more than 50 gallons and add 1 gallon of oil and then add what I need to the remaining or stop at 100 gallons and add another gallon of oil and add then start filling again. I was on my buddies boat once and we were coming back in and his low oil sensor started going off. He had just got the boat and didn't know it well. It is hard to keep running with the sensor going off with knowing you have a 1/4 of oil and is the sensor bad or is it not pumping oil. At first I didn't like having to premix but now I know it is one less thing to worry about. just my opinion.


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## splitshot (Mar 14, 2008)

i like premix, it might smoke a little more, but you know that it gets enough but not too much either...costs a good bit of money to rebuild one, i haveNEVER trusted the premix systems, maybe its just me...if the VRO systems fails and you dont realize it in time, be prepared to spendALOT of money....its just easier to pour in the oil and gas and that will be one less thing to worry about while fishing or boating


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## Play'N Hooky Too (Sep 29, 2007)

Thanks for the advice ya'll. My biggest problem right now with pre-mixing is determining how much gas is in the tank to start with. The gage shows about3/4a tank but I know that that actually means about 1/2 because I can putanother 20-25 gallons in it afterthe gage pegs out at full. Doing the math to determine how much oil to put in from this point forward would not be a problembecause they taught me how tocifer reel good in injuneerin skool.


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## outbrdwrench (Apr 8, 2009)

*As far as all "VRO" oil injection systems go, I trust OMC the least! It is pulse driven instaed of gear driven. But it is also the fuel pump, So like davlor said it should be relpaced if it ismalfunctioning, butall the hoses, pulse limiter etc, also need to be inspected for properoperationif you plan to rely on it! Most of the other injection systems on the maket are very reliable .All These motors are designed to operate with <U>VARIABLE</U> oil injection ststem because of the motor's optimum oil requirements. most injection systems deliver 50;1 at WOT, but idle at 100:1. for conventional induction, & as low as 400:1 onsome direct injected 2-strokes at idle. When you pre-mix, you are always at 50:1. Not only do these motors develop alot more carbon build up (idle is when it accumilates the worst), which in turn makes it smoke even worse, they use considerablymore oil (not cheap if you'r using the right stuff)."Variable Ratio oiling" is just that! Yamaha's "Precision Blend" system is by far the most dependable system on the market, but it too, still needs to be MAINTAINED! outbrdwrench.*


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## DOUBLE "D" & LV (Oct 2, 2007)

Instead of trying to figure how much oil to put into an unknown fuel supply amount, put in enough oil for the capacity of the tank and fill it up. Now you know you have the right mix and can start from scratch to keep up with the fuel burnt.


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## Play'N Hooky Too (Sep 29, 2007)

> *DOUBLE "D" & LV (8/2/2009)*Instead of trying to figure how much oil to put into an unknown fuel supply amount, put in enough oil for the capacity of the tank and fill it up. Now you know you have the right mix and can start from scratch to keep up with the fuel burnt.


That would indeed be the best method. 

Thanks


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## reefcreature (Oct 3, 2007)

> *DOUBLE "D" & LV (8/2/2009)*Instead of trying to figure how much oil to put into an unknown fuel supply amount, put in enough oil for the capacity of the tank and fill it up. Now you know you have the right mix and can start from scratch to keep up with the fuel burnt.


but wouldn't that work on empty fuel tanks? in other words if your tank is 1/2 full but your gauge is reading 1/4 you would end up with too rich oil mix wouldn't you?


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## Play'N Hooky Too (Sep 29, 2007)

> *reefcreature (8/2/2009)*
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> > *DOUBLE "D" & LV (8/2/2009)*Instead of trying to figure how much oil to put into an unknown fuel supply amount, put in enough oil for the capacity of the tank and fill it up. Now you know you have the right mix and can start from scratch to keep up with the fuel burnt.
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Basically what he is saying is that if I have a 100 gallon tank with an unknown quantity of unmixed fuel currently in it, go ahead and put in2 gallons of oil and then fill the tank up to the full capacity.At that point I would have 100 gallons of mixed fuel with a ratio of 50:1 (well actually 49:1).From that point forward I would then just have to add the proper amount of oil for the amount of gas I put in at each fill-up.


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## reefcreature (Oct 3, 2007)

ok! my fault. i missed the *"unmixed fuel" *part. yes that makes sense now.:doh


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## gizzy (Jun 24, 2009)

I have a 150 Evinrude VRO and the last owner's mechanic took it off after he blew hi powerhead.And put a new rebuilt on it. So what I do as far as pre-mixing is instead of using quarts into gals. It's easier to use 1 liter of oil to every 10 gals.of gas. This is a much easier way to gauge 50:1 ratio. West Marine has a liter bottle measured in 10 decimeter increments. When I get gas, remember how many gals. you get. This will assure you on haw much oil to put in your tank. Never had any problems since the pump went out.


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## pb&jellyfish (May 1, 2008)

I have a 70hp Johnson VRO running premixed. The pump went bad and the owner decided not to replace it when he discovered how expensive it would be. I don't have a problem running it the old fashioned way, but if the VRO was working properly, I would probably keep it just for convenience.


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