Re: D/C Oil Tank on 88' 90hp Johnson VRO?
Many people are "afraid" that a malfunctioning VRO is going to "blow" their outboards powerhead. This is primarily due to untrained, uneducated "mechanics" (I use the term loosly) and "parts-swappers" who are too lazy to figure out why things fail.<br /><br />The VRO/OMS pumps are a relatively simple device. The pump has 3 sections: an air motor, in which a diaphragm, driven by crankcase pressure and vacuum pulses operates the other 2 sections. A diaphragm type fuel pump and a piston style oil pump. Basically fuel and oil are drawn from their respective tanks in your boat and mixed in an internal chamber of the pump. Mixed fuel and oil is sent to all carburetors - the unit cannot selectively oil or not oil an individual cylinder. Its all, or none at all.<br /><br />Now with that said: Can one of these pumps fail? Yes, its a mechanical device assembled by a human. Mechanical devices and the rubber components inside this one can break down over time. And the assembling human can put it together wrong - usually it will fail quickly if misassembled. <br /><br />Now, the most common failure of one of these guys is the air motor diaphragm. But when it fails, the pump doesn't work - period. That means it don't pump gas or oil, the motor doesn't run and a motor that can't run, can't "blow". OK, what about the other portions of the pump? If the fuel diaphragm fails, again the motor ain't goin' no-where. If the the oil piston fails, there is a "no-oil" alarm (in-fact, it's still the ONLY oiling system with a "no oil delivery" alarm). Can it AND the alarm system fail? Yes, BUT, it is EXTREMELY rare.<br /><br />I had a good customer come into our shop a couple years back with his "blown" 150 Fastrike. He's mad as hell when he pulls up. It took me awhile to calm him down and get his story - He's got the family and friends from out of town out in his boat. Nice beautiful day, runnin' along at 4-grand. All of a sudden, the engine looses power and locks up, no bells, no wistles, no alarms. Won't even turn over. Back to the ramp with the electric motor. Hand loads on the trailer, week-end ruined. Stops by the local "mechanic" at the lake. Wonder-boy has a look - "Yup" he says "its locked up, let me pull the cylinder heads..." A few minutes later he says "Looky here, all 6 cylinder deeply scored. Your VRO failed." <br /><br />Well, I go out and have a look. Sure enough all 6 are toast. Pull the drain screw out of one of the carbs and find gas & water. Hmmm. Pull the oil supply hose, looky HERE water. Hmmmm. Go look in the boat and pull out the oil reservoir - an inch and a half of water in the bottom. BTW, I tested the pump it STILL worked.<br /><br />The bottom line: Oil injection is a nice convenience. But like anything else, it needs periodic maintenance IF you expect to get a long service life out of it.<br /><br />Should you remove it? That's entirely up to you, but it involves a little more than just plugging the oil line and removing the tank. You also have to disconnect the alarm system wires, or you're going to get a rash of false alarm warnings.<br /><br />Sorry to be so long winded, hope this info helps.<br /><br />-John
