Q about priming oil in pump w/VRO

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Mark42

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I am going to start up a freshly rebuilt 2004 Johnson 90 hp V4. I'm wondering how to tell if the oil is reaching the VRO pump when the primer bulb gets hard.

I know that my 1994 40 hp Evinrude has a small section of white plastic hose (1/2-3/4" long) in the oil line just one inch or so from the pump. So it was easy to tell if the oil had been pumped up to the VRO pump.

The 90 hp does not have that piece of plastic hose (that I can see or is listed in the service manual). So the best I can tell is where I connect the VRO tank to the hose coming off the pump. That length of hose from the tank to the connection point is easily about 18" long.

Any suggestions to know if the oil has reached and filled the VRO pump before starting?

Thanks!
 

Chris1956

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Re: Q about priming oil in pump w/VRO

Mark, the service manual is specific. Pump the oil line primer until all air is out of it. Now attach it to the OMS pump and pump it one more time. Now attach a 50::1 oil-gas fuel mix and run it until you can verify the OMS pump is supplying oil (see it drop in the resevoir).

fresh rebuilds normally require a 25:;1 fuel mix anyway, so you should be running 50::1 premix anyway, in additon to the OMS supplying oil.
 

Mark42

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Re: Q about priming oil in pump w/VRO

Mark, the service manual is specific. Pump the oil line primer until all air is out of it. Now attach it to the OMS pump and pump it one more time. Now attach a 50::1 oil-gas fuel mix and run it until you can verify the OMS pump is supplying oil (see it drop in the reservoir).

fresh rebuilds normally require a 25:;1 fuel mix anyway, so you should be running 50::1 premix anyway, in additon to the OMS supplying oil.

Yes, you are right about what the manual says.

The problem is how to tell that the oil is actually being pumped before spending a few hours operating the boat. If the pump is sucking air, then the motor is only running on 50:1 mix, and not the 25:1 mix it is supposed to use.

To make any significant or measurable drop in the oil tank, it will take hours of running. I don't want to put two hours on the motor before I find out the VRO pump is just sucking air.

If the oil primer is pumped before the fuel line, will it bleed out the air in the oil side into the fuel side? Then the fuel can be pumped up? Its easy enough to see the fuel, one top carb fuel lines can be removed while pumping the fuel primer to see the fuel pump out.

Any suggestions to verify before leaving the marina?

I just don't have a lot of faith that the technician ensured the VRO pump is operating proper before shipping. The shop foreman told me the motor was run for 45 minutes in a test tank with a test prop fixture. Hope that info is correct.

Guess I just have a case of the jitters getting so close to running the new motor.
 

Chris1956

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Re: Q about priming oil in pump w/VRO

The only way the be safe and sure is to idle around for an hour and carefully watch the oil level drop. if you idle only, the 50::1 fuel mix is sufficient for a rebuild break-in.

Do you suspect the OMS pump?
 

Fed

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Re: Q about priming oil in pump w/VRO

My older 1988 VRO2 manual says to prime the oil side first but if you prime the fuel side first then you must prime the oil side with the engine running. Note: The no oil warning horn will sound until the oil reaches the VRO2 pump.
All this is with 50:1 premix of course.
Sounds like a good way to test the alarm too.
 

yoster

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Re: Q about priming oil in pump w/VRO

My OEM manual states to pre-mix the gas 50:1 AND hook up the VRO pump during break-in.

I'd suggest you do the same. You'll be smoky, but you'll be able to run the boat however you wish for a few hours, with no worries about lack of oil since you'll be pre-mix, and you'll still be able to check and verify a drop in the oil tank.
 

Dhadley

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Re: Q about priming oil in pump w/VRO

We have always done pretty much what Fed suggests. 50:1 in the tank and we pump the oil almost all the way to the pump, hook it up and start the motor. The no oil alarm will sound telling us it works and it will quit when the pump gets the oil. That means that part works too. At idle 50:1 is way more than it needs so there's no danger of hurting the motor.
 
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Re: Q about priming oil in pump w/VRO

The proper way to change and verify if the VRO is properly mixing oil is to change out everything that comes with the kit: Pulse limiter, fittings, orings etc.
How do you know if you bought the kit? Well for one it costs about 340 bucks over the counter, another is it comes with a lot more stuff than you need. Second be sure that you use good tie straps to secure fittings do not use hose clamps, they tend to damage the hose and do not responds well to vibration and temperature changes. I recommend part number 54816311T, this is a Mercury part number but BRP has the same strap but don't know the part number. Once you look at the buckle of the strap you will understand why it is better, in fact I recommend this strap for all hose fittings that deal with fuel and oil. Make sure that the straps are tight. I use the closed end of a 1/4" wrench and vise grips to secure them. (Put the bitter end of the strap thru the closed end of the wrench and pull, works really well considerding that BRP has and apparently with always love building components out of plastic). After all of the hoses are in the correct place EXCEPT FOR THE OIL LINE have someone gently squeeze the primer bulb of the oil tank, have something to catch the oil and once you see solid oil, no air bubbles, quickly attach the oil line to the VRO and secure line with tie strap. At this time I would examine the oil tank filter screen and lines. Dump any old, substandard oil, yes their is a difference between oils! The proper oil to use is XD30 or XD50 or any of the manufacturers TCW3 Oils. Fill the oil tank about 1 inch from the top, mark the level line with a sharpy marker. Next time you fill up properly mix a 50:1 ratio of OEM TCW3 oil in the boats fuel tank and just go boating. Watch the fuel gauge and at about 1/2 capacity go back and examine the mark on the tank. If the oil line has dropped you are consuming oil. Remember VRO stands for variable ratio oiling. So the faster you go the more oil will be used so if you putt around and go back and check your consumption will be less than if you run it at your top end rpm.
Their is a way to properly check if the VRO is consuming oil but the test takes close to an hour to complete so at $100/hr you can see the benefit of just changing the VRO. But also remember the VRO is a combination fuel/oil pump, so if you are on a budget mose people just premix their fuel in the gas tank and disable the alarm, in fact BRP makes a kit for this...hope this helps
 

Mark42

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Re: Q about priming oil in pump w/VRO

The only way the be safe and sure is to idle around for an hour and carefully watch the oil level drop. if you idle only, the 50::1 fuel mix is sufficient for a rebuild break-in.

Do you suspect the OMS pump?

No, I don't suspect that it doesn't work. Just reading the breaking procedure, it was not clear to me if the pump was getting oil or not and how to tell.

My older 1988 VRO2 manual says to prime the oil side first but if you prime the fuel side first then you must prime the oil side with the engine running. Note: The no oil warning horn will sound until the oil reaches the VRO2 pump.
All this is with 50:1 premix of course.
Sounds like a good way to test the alarm too.

This is a 2004 OMS system (I know I wrote VRO, but that is just habit from my 94 Johnson 40 hp). I'll review the procedure again, and be sure its OK to get the alarm until oil hits the pump.


We have always done pretty much what Fed suggests. 50:1 in the tank and we pump the oil almost all the way to the pump, hook it up and start the motor. The no oil alarm will sound telling us it works and it will quit when the pump gets the oil. That means that part works too. At idle 50:1 is way more than it needs so there's no danger of hurting the motor.

Thanks Dhadley, I appreciate you taking the time to verify what others said.
 

Dhadley

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Re: Q about priming oil in pump w/VRO

No problem! Keep us posted on how it works out for you, very good motor BTW.
 

Mark42

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Re: Q about priming oil in pump w/VRO

No problem! Keep us posted on how it works out for you, very good motor BTW.

This afternoon the last connections were made and turned the ignition on. The System Check lights came on in the tachometer, and the "low oil" light came on, but no alarm. Oil was added to the tank and the light went off. So the oil tank switch and wiring is working right. Thought the alarm should have went off.

After pumping up the oil and gas, the motor was started. I let it idle at slightly high idle, about 1100 rpm and no warning lights or alarm. After a minute or so of run time, the no oil light comes on. I tried pumping the oil primer bulb but it didn't help. Alarm is not going off.

After a minute or two, the motor started to stumble and stalled. The fuel primer bulb was pumped until hard (brand new primer bulb just installed) and it seamed to idle ok. The oil light still is on and again, the alarm did not go off.

After that, I had to shut it off as I had run out of time and some other obligations to take care of.

So thats it. Tomorrow the connections for the alarm will be tested with a multi meeter, as well as testing the alarm horn itself.

How long does it take before oil will fill the pump? And shouldn't the alarm be sounding?
 

Mark42

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Re: Q about priming oil in pump w/VRO

This morning I took the alarm horn off the wire harness and tested it. Dead. Hooked up a spare horn, and the horn beeps when ignition is turned on.

Pumped up the oil line, and then the fuel line, and started the motor. It ran for a few minutes, before stumbling and died. Pumped up the fuel, and I could hear fuel moving through the bulb. Must still have had some air in the fuel lines. Started motor again, and it continued to idle, making lots of smoke, so I assume the OMS is working. Then after a few minutes, the alarm goes off, and its the "no oil" light. But the exhaust is still very smokey, so I am confused.

I read the owners manual and service manual. They say when any part of the oil system is changed, the oil pump must be primed. And it must be primed before the fuel side. Apparently if the fuel side is full of fuel, the oil can not come in and fill the oil side. So I disconnected the fuel line, and ran the motor until it started to sputter/misfire and shut it off. The fuel pump should be empty at this point. The oil line was disconnected at the connection just outside the motor, and primer was pumped until 12 oz were pumped out of the oil line. Then it was connected to the motor oil line, and primer bulb pumped up (about 3/4 pumps). Then the fuel line connected and the motor started.

It smoked more than even before, but after a minute or two, I bumped up the idle to about 1100 - 1200 rpm and then the alarm sounded and the "no oil" light came on again!!!!

Shut off and restarted, and after two minutes or so same thing.

What could be causing the no oil light to come on after a few minutes of idle time? Oil primer bulb is hard. Think there is still air in the oil line?

Maybe I should switch it over to all premix?
 

Fed

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Re: Q about priming oil in pump w/VRO

Blocked filter in oil tank, restriction in oil lines (kinked or squashed), air leak in oil lines.
Sounds like you could have an air leak or restriction in your fuel system too.
 

Mark42

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Re: Q about priming oil in pump w/VRO

Blocked filter in oil tank, restriction in oil lines (kinked or squashed), air leak in oil lines.
Sounds like you could have an air leak or restriction in your fuel system too.

Installed new filter in oil tank, pumped 12 oz of oil from tank to motor connection, checked for kinks and all oil line is new with this install. Fuel lines were checked, new primer bulb, and fuel pumps through the lines easily with the primer bulb.

Thanks for the suggestions. I am re-reading the owners manual and service manual even as I write this.

With the System Check system, can the oil pump be bypassed by just plugging the line, and disconnection the one wire harness to the OMS pump? Or will that trigger the SLOW system?
 

Fed

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Re: Q about priming oil in pump w/VRO

With the System Check system, can the oil pump be bypassed by just plugging the line, and disconnection the one wire harness to the OMS pump? Or will that trigger the SLOW system?
I can't say for sure so I'll leave that for someone who knows positively.
You do know that when you prime the oil you should disconnect the input line at the oil pump, prime until all bubbles are gone then reconnect the line & prime one more squeeze?
Do you have the OEM manual?
 

Mark42

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Re: Q about priming oil in pump w/VRO

I can't say for sure so I'll leave that for someone who knows positively.
You do know that when you prime the oil you should disconnect the input line at the oil pump, prime until all bubbles are gone then reconnect the line & prime one more squeeze?
Do you have the OEM manual?

yep, the OEM manual. Both service and owners. I don't like aftermarket manuals.
 

Mark42

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Re: Q about priming oil in pump w/VRO

Update: Yesterday evening I removed the mid section cover and removed the oil hose from the OMS inlet fitting. There was oil right there, and some dripped out of the OMS pump. Had someone squeeze the primer bulb until about 6 oz were pumped through. No air bubbles or anything unusual in the oil being pumped out. So the oil line was re-connected. Inspected the wire harness, it looked fine, and the clamp holding the plug together was there.

I'm thinking of mixing the fuel at 25:1 for the initial trip and see if the oil light goes off. If not, then the motor is still being protected by a 25:1 mix during break-in.

Any suggestions?
 

Chris1956

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Re: Q about priming oil in pump w/VRO

That will work, however, if the OMS starts to work you will be at 16::1, which is pretty smokey.

Why not just pre-mix the fuel at 50::1 and keep the revs down until you determine if the OMS pump is working?
 

Joe Reeves

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Re: Q about priming oil in pump w/VRO

(Priming The VRO Pump)
(J. Reeves)

When hooking up or installing a VRO whether it is a new or original VRO pump, it must be primed in order to dispel any air that might be in the oil line.

Have the Oil line attached to the engine fitting BUT detached from the VRO. Add a piece of fuel hose if necessary to the oil line so that it can be aimed into some sort of container.

Pump the oil primer bulb, catching the oil flowing out of the line into the container until you are absolutely sure that you have rid the oil line of every bit of air that might have been trapped there.

Now, connect the oil line to the VRO and secure it. When the oil line is secured, apply pressure to the oil primer bulb ONE TIME only. That's it.
 
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