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Author Topic:   1991 150 Johnson Automatic Oil Mixing

c whale posted 04-23-2007 08:05 AM ET (US)
I am looking at purchasing a 1982 outrage 25 w/ twin 1991 Johnson 150's. In talking to the guy who is selling it, he said the engines run fine, but that he had taken off the oil/gas mixing units in favor of adding the oil into the main tank. With a 140 gallon tank size, I would rather not have to deal with mixing oil into the main tank, so my questions are the following:
Were there problems with the mixing units for this year and model?
If so, can I replace them with a newer model that did not have problems?
Are these generally good and reliable engines?
Thanks for any help,
Hunter
jimh posted 04-23-2007 09:52 AM ET (US)
There has been a great deal of prior discussion about the OMC automatic oil mixing system, known often as VRO but more properly OMS. Read this article:
The Myth of the Mixer
http://continuouswave.com/whaler/reference/VRO.html
You can re-install the OMS pump on your engine with the latest model. You can get parts at a BRP dealer. A new pump will be about $250. I hope you have the oil reservoir tanks and all of the associated hoses, primers, wiring harnesses, and so on. If not, replacing all of that will be a bit expensive.
There is also an update for your engine which will permit you to use the newer style SystemCheck gauge. This provides better alarm signaling from the engine to warn of problems. I have a 1992 Evinrude motor and I installed the update for the SystemCheck gauge. The update kit ($300) includes new oil lines and oil pick up, new wiring harnesses, and other miscellaneous stuff. So if you are missing the oil lines from the original installation because the previous owner discarded them, this is a good way to get them replaced. You would then just need to buy a new oil reservoir tank ($100) to complete the overhaul.
The 150-HP V6 OMC engines are generally considered to be simple and decent engines. With my 1992 engine I have recently had to replace some electrical components. I think this is typical. I have installed a new rectifier and voltage regulator assembly ($225), a new Power Pack ($250), and a new starter circuit solenoid ($25). I think these repairs are tolerable for a 15-year-old motor. I was not the original purchaser of the engine, and some of these problems may have been part of the reason the previous owner sold the boat. They were devilishly intermittent and it took me a while to find and repair them all.
c whale posted 04-23-2007 11:09 AM ET (US)
Thanks Jim, that is very valuable info. I will definitely take all that into consideration when considering this purchase.
Hunter
contender posted 04-24-2007 08:08 AM ET (US)
C whale, do not waste your money, unless you have a bottom less pit of money and just want it. Keep mixing the oil in the gas its working fine and you never have to worry about it breaking. Spend your money on some other things for the boat like gas. Go out and enjoy your new toy...good luck
bms1939 posted 04-26-2007 11:48 AM ET (US)
I have a 200 gallon tank that I mix the oil in the gas. The only [problem] I've ever had was my gas gauge was off and filled the boat not leaving room for the oil. Then I put the oil in first and couldn't put enough gas in for the amount of oil. I've been doing it for seven seasons now, after the two mishaps no problems at all.
fourdfish posted 04-26-2007 02:16 PM ET (US)
I had a 175hp Johnson Fast Strike for 14 years. The oil pump work just fine for all those years. I also know several other
Fisherman who had those oil pumps on the engine and none of them ever had a problem with them.
Sal DiMercurio posted 04-26-2007 08:56 PM ET (US)
1991 was the first year OMC came out with a 60 degree "V"6 150 & 175 hp.
They are very reliable engines.
The VRO on my 1997 - 70 hp Johnson went out [ pumping to much oil ] & it is part of the fuel pump, & that whole unit is $400 for the 70 hp, I have to think it would be at least that much for the 150 hp unit.
If your VRO's [ twin engines ] is already disconnected, I would leave it alone.
When youir filling your tank & know it's getting close to the top, just use the measuring cup that is sold at the dealer for 50.1 mix.
Remember this, even if you mix it at 60.1 you will be fine as long as you don't run at wide open throttle all day long.
The only time your engine will need the true 50.1 mix is while running at wot.
If your trolling, your only going to need may 100.1 - 150.1 mix.
At cruise [ approx 4000 rpms ] your engines will only need approx 65.1 - 70.1 mix so don't be paranoid if you put a bit less or a bit more oil, just as long as your close to 50.1 - 75.1 & you run the engines like a sane person you should be just fine.
I don't think I'd sink over $1,500 into oiling systems at this stage of the game on 16 year old engines.
If 1 craps out, what would you do?
Would you put 1 new e-tec with the 1 engine thats still running or buy 2 new engines?
Those engines could last another 10 years with no problems, & they could also blow next week.
Sal.
tmann45 posted 04-27-2007 07:16 AM ET (US)
Hunter, I, like you, did not want to premix in my 115-gallon tank when my Mercury oiling system went out. However, it has not been the pain the the a$$ that I thought it would be. I have a FloScan installed so I know how much gas I will be adding within a gallon or two. I usually fill up when I buy gas. If I am adding more than 50-gallons, I add a gallon of oil and then 50-gallons of gas. Then I figure and add the remaining oil (estimating from a gallon jug) and gas. An alternative method would be to buy gas in 50-gallon increments and add a gallon of oil. This would be difficult without the FloScan, trying to use the fuel gauge only.
Tom
jgkmmoore posted 04-28-2007 02:07 PM ET (US)
Premix really is not any more of a problem than VRO, but will use more oil over time because it's always 50:1.
Carry a 2 1/2 gal spare tank.Pour in a gallon of gas, then however much oil you need for your buy, shake it and pour into the main tank.Then fill your main tank.
Of course, you need to know how much gas you will buy before you start mixing.With this method, you know your oil is fully mixed. It may cost you a minute or two, and one xtra pour.Cheap insurance.
If you forget..........your motors will slow suddenly, then stop.If you can see thru your tears, call Seatow. This is why most boats with large outboards always carry a box of tissues.

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Author	Topic: 1991 150 Johnson Automatic Oil Mixing
c whale	posted 04-23-2007 08:05 AM ET (US) I am looking at purchasing a 1982 outrage 25 w/ twin 1991 Johnson 150's. In talking to the guy who is selling it, he said the engines run fine, but that he had taken off the oil/gas mixing units in favor of adding the oil into the main tank. With a 140 gallon tank size, I would rather not have to deal with mixing oil into the main tank, so my questions are the following: Were there problems with the mixing units for this year and model? If so, can I replace them with a newer model that did not have problems? Are these generally good and reliable engines? Thanks for any help, Hunter
jimh	posted 04-23-2007 09:52 AM ET (US) There has been a great deal of prior discussion about the OMC automatic oil mixing system, known often as VRO but more properly OMS. Read this article: The Myth of the Mixer http://continuouswave.com/whaler/reference/VRO.html You can re-install the OMS pump on your engine with the latest model. You can get parts at a BRP dealer. A new pump will be about $250. I hope you have the oil reservoir tanks and all of the associated hoses, primers, wiring harnesses, and so on. If not, replacing all of that will be a bit expensive. There is also an update for your engine which will permit you to use the newer style SystemCheck gauge. This provides better alarm signaling from the engine to warn of problems. I have a 1992 Evinrude motor and I installed the update for the SystemCheck gauge. The update kit ($300) includes new oil lines and oil pick up, new wiring harnesses, and other miscellaneous stuff. So if you are missing the oil lines from the original installation because the previous owner discarded them, this is a good way to get them replaced. You would then just need to buy a new oil reservoir tank ($100) to complete the overhaul. The 150-HP V6 OMC engines are generally considered to be simple and decent engines. With my 1992 engine I have recently had to replace some electrical components. I think this is typical. I have installed a new rectifier and voltage regulator assembly ($225), a new Power Pack ($250), and a new starter circuit solenoid ($25). I think these repairs are tolerable for a 15-year-old motor. I was not the original purchaser of the engine, and some of these problems may have been part of the reason the previous owner sold the boat. They were devilishly intermittent and it took me a while to find and repair them all.
c whale	posted 04-23-2007 11:09 AM ET (US) Thanks Jim, that is very valuable info. I will definitely take all that into consideration when considering this purchase. Hunter
contender	posted 04-24-2007 08:08 AM ET (US) C whale, do not waste your money, unless you have a bottom less pit of money and just want it. Keep mixing the oil in the gas its working fine and you never have to worry about it breaking. Spend your money on some other things for the boat like gas. Go out and enjoy your new toy...good luck
bms1939	posted 04-26-2007 11:48 AM ET (US) I have a 200 gallon tank that I mix the oil in the gas. The only [problem] I've ever had was my gas gauge was off and filled the boat not leaving room for the oil. Then I put the oil in first and couldn't put enough gas in for the amount of oil. I've been doing it for seven seasons now, after the two mishaps no problems at all.
fourdfish	posted 04-26-2007 02:16 PM ET (US) I had a 175hp Johnson Fast Strike for 14 years. The oil pump work just fine for all those years. I also know several other Fisherman who had those oil pumps on the engine and none of them ever had a problem with them.
Sal DiMercurio	posted 04-26-2007 08:56 PM ET (US) 1991 was the first year OMC came out with a 60 degree "V"6 150 & 175 hp. They are very reliable engines. The VRO on my 1997 - 70 hp Johnson went out [ pumping to much oil ] & it is part of the fuel pump, & that whole unit is $400 for the 70 hp, I have to think it would be at least that much for the 150 hp unit. If your VRO's [ twin engines ] is already disconnected, I would leave it alone. When youir filling your tank & know it's getting close to the top, just use the measuring cup that is sold at the dealer for 50.1 mix. Remember this, even if you mix it at 60.1 you will be fine as long as you don't run at wide open throttle all day long. The only time your engine will need the true 50.1 mix is while running at wot. If your trolling, your only going to need may 100.1 - 150.1 mix. At cruise [ approx 4000 rpms ] your engines will only need approx 65.1 - 70.1 mix so don't be paranoid if you put a bit less or a bit more oil, just as long as your close to 50.1 - 75.1 & you run the engines like a sane person you should be just fine. I don't think I'd sink over $1,500 into oiling systems at this stage of the game on 16 year old engines. If 1 craps out, what would you do? Would you put 1 new e-tec with the 1 engine thats still running or buy 2 new engines? Those engines could last another 10 years with no problems, & they could also blow next week. Sal.
tmann45	posted 04-27-2007 07:16 AM ET (US) Hunter, I, like you, did not want to premix in my 115-gallon tank when my Mercury oiling system went out. However, it has not been the pain the the a$$ that I thought it would be. I have a FloScan installed so I know how much gas I will be adding within a gallon or two. I usually fill up when I buy gas. If I am adding more than 50-gallons, I add a gallon of oil and then 50-gallons of gas. Then I figure and add the remaining oil (estimating from a gallon jug) and gas. An alternative method would be to buy gas in 50-gallon increments and add a gallon of oil. This would be difficult without the FloScan, trying to use the fuel gauge only. Tom
jgkmmoore	posted 04-28-2007 02:07 PM ET (US) Premix really is not any more of a problem than VRO, but will use more oil over time because it's always 50:1. Carry a 2 1/2 gal spare tank.Pour in a gallon of gas, then however much oil you need for your buy, shake it and pour into the main tank.Then fill your main tank. Of course, you need to know how much gas you will buy before you start mixing.With this method, you know your oil is fully mixed. It may cost you a minute or two, and one xtra pour.Cheap insurance. If you forget..........your motors will slow suddenly, then stop.If you can see thru your tears, call Seatow. This is why most boats with large outboards always carry a box of tissues.