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Random Quote: In theory, practice and theory are the same, but in practice they are diffrent. (Larry McVoy)
My 97 Evinrude runs great, doesn't foul plugs and has about 700 hours. I have been thinking about disconnecting the oil injection and going to premix. But the old saying "if it aint broke, don't fix it" comes to mind. My mechanic says the oil injection systems are very reliable and he doesn't recommend disconnecting it.
What do you guys think?
__________________ Scubadown
1981 Grady White 24 Offshore
1997 200 HP Evinrude
The oil injection is still hooked up on my 2000 yr model Johnson, it works fine and I dont have any plans to disconnect it. From what I have heard the VRO problems were mainly late 80's to early 90's.
__________________ Sea Hunt Triton 200- 130 Johnson
My 97 Evinrude ... my mechanic says the oil injection systems are very reliable and he doesn't recommend disconnecting it.
Well, if yours is "in trouble" , then mine is too !
Let it be known that OMC replace their previous oiling system VRO (Variable Ratio Oiling) with their new design OMS (Oil Metering System) in early 90s. These are pretty much bulletproof.
Run the right pitch on that prop, use good quality fuel and premium oil, and decarb using Seafoam every 50-60 hours ... and that puppy will last you a long time ... albeit she'll be a thirsty one .
__________________ [red]MISS TEAK[/red], 25' Parker mod-V Sport Cabin "Life's too short to own an ugly boat ..." www.classicparker.com
many guys down here disconnect & go to premix after their warranty expires...the reasoning is that if you have an injection failure, you won't know about it till your motor is blown
my buddy just blew up a 1997 ox66 200 after one of his injectors clogged...
So what is the down side of disconnecting the oil injection? Greater chance of fouled plugs and slight increase in oil consumption. Right now I average about 60 to 1 and I guess I would pre-mix at 50 to 1.
__________________ Scubadown
1981 Grady White 24 Offshore
1997 200 HP Evinrude
Mine's disconnected. Can you imagine Ford or GM using a rubber hose running from the oil pump, with plastic clamps to lubricate their motors in cars? And they're not exposed to the beating and salt water. Many different opinions on this.
I would not disconnect it if it's working fine. From my understanding of how the OMS system works, if the oil pump fails then the fuel pump will also fail (air motor). No oil, no fuel then no damage.
Now should the pump (fuel/oil) fail, then you can get just the fuel pump and blank the oil pump. I'd do it in that case.
A lot of blown pistons have been blamed on faulty oil injection systems, when it really was a carb problem.
I too believed that "if it aint broke don't fix it"until............
In 2002 my 1994 Evinrude's oil injection quit working and killed what up to that point had been a really reliable, workhorse 70 hp motor. I believe mine was one of the newer so called "bullet proof" versions. Most mechanics I talked to recommended removing the OMC/Evinrude oil injection after the warranty expired. Your mechanic may be looking forward to the up and coming rebuild so he's recommending you continue to use the oil injection. I didn't listen to my mechanic and paid dearly for the mistake ($6500 repower). Pre-mix oil may foul things up a bit but no oil is absolute failure. Go with your gut on this one. Your unit may last forever but something tells me you should probably disconnect to be safe. If $$$$ isn't an issue then just keep using it until she drops dead soon or many years down the road.
first thing i did when i bought my current boat was diconnect the oil injection pump(used 93 150 evinrude). i had a 89 150 mercury blow up do to a oil pump failing. you might foul out some plugs but at least you wont blow an engine.
You'd better go right outside and chop off your foot because you might get an ingrown toenail....
Seriously, don't fix what ain't broke. And if it does break, what 's the worse that can happen? If the engine sees low oil, you'll get an alarm. If it progresses to "no oil" your engine shuts down...so keep some oil on board in case ths happens...why put yourself through a lot of extra work and hassle???
VRO Pump Conversion To Straight Fuel Pump
(J. Reeves)
You can convert the VRO pump into a straight fuel pump, eliminating the oil tank and VRO pump warning system, but retain the overheat warning setup by doing the following:
1 - Cut and plug the oil line at the engine so that the oil side of the VRO pump will not draw air into its system. Trace the wires from the back of the VRO to its rubber plug (electrical plug) and disconnect it.
2 - Trace the two wires from the oil tank to the engine, disconnect those two wires, then remove them and the oil tank.
3 - Mix the 50/1 oil in the proper amount with whatever quanity fuel you have. Disconnect the fuel line at the engine. Pump the fuel primer bulb until fuel exits that hose with the tint of whatever oil you used. Reconnect the fuel hose.
Look here for a good discussion on the VRO system:
HullSlap,
When your 70hp failed, was it only #2 cylinder, or did the whole motor freeze up due to lack of oil. If so, the crankshaft should have been "blued" and scored and not repairable. All rods and bearings should have been shot, and all 3 piston and cylinders should have been deeply scored. Possibly only the block could have been bored and everything else would need replacing, making it cheaper to buy a new or different powerhead. Now if the crank was OK, along with a rod or two, then you did not have a lack of lube problem.
Sounds like you might want to find an OMC trained tech to get the real story on this. People like pre mix because they are in control of that, not a mechanism, but people have messed up pre mix too. It works fine with lawn equipment where you are working with a gas can with a few gallons at most, but since most marinas around here dont even have a pump that reads out in gallons like a car pump, there is a definite margin for error with pre mix as well.
__________________ 1988 Four Winns 200 Horizon
4.3 OMC Cobra
1998 Jeep Grand Cherokee
4.0/NV 242 Selectrac
2007 Jeep Grand Cherokee Limited
5.7 HEMI/Quadradrive II
The old VRO's were problematic and we used to discontect them for customers. I haven't worked on boats for a living for several years but haven't heard many horror stories with the newer oiling systems.
Seahorse:With a 6500.00 tab, I'm sure hullslap must have meant he had the powerhead replaced not rebuilt (and some other work down at the same time) At least I hope so!
The less stuff, the less stuff to go wrong. Disconnect that bad boy and just pre-mix 50:1. When you put it in there yourself ... you know it's in there!
Remember, VRO and its progeny are the gems of OMC - just like FICHT!
HullSlap,
When your 70hp failed, was it only #2 cylinder, or did the whole motor freeze up due to lack of oil. If so, the crankshaft should have been "blued" and scored and not repairable. All rods and bearings should have been shot, and all 3 piston and cylinders should have been deeply scored. Possibly only the block could have been bored and everything else would need replacing, making it cheaper to buy a new or different powerhead. Now if the crank was OK, along with a rod or two, then you did not have a lack of lube problem.
Everything was shot. Mechanic showed me the disassembled motor. The damage was extensive. All three cylinders were deeply scored etc. Repairing was still cheaper than repowewring but I didn't want to put $4000 into an old motor when I could buy new for about $5900 plus install. Next time I'll go to pre mix just so I feel a little more in control. Actually next time will probably be a 4-stroke for me which will open up a whole new set of concerns.
Disconnect Oil Injection? 
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