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Johnson Outboard vro 1987 omc V4

This is where I am at now. I installed all new hose & clamps. Also the reservoir is very clean and I pulled the unit out of the tank and filter was also very clean. The oil flows very freely and I purged the line of any air right up to where it connects to the VRO, with my helper squeezing just slightly on the bulb just until a little oil came out of the end of the hose, I admediatly connected it to the VRO and clamped it. Then started the engine with the fuel line plugged into my premix gas tank from the other boat, Started the engine and afterwards while running I gave the bulb one squeeze ONLY, and no alarms. I then switched back to the main gas tank (straight fuel) (non ethanol) and so far everything seems to be fine (no alarms)

One puzzling thing though, after the engine has been running for a while, it is running out of fuel in the line from the tank. I have all brand new hoses & clamps, there is no air leaks, I have teflon tape on all the fittings going into the gas tank and they are all tight. The suction tube in the tank has no restrictions, I even removed the wire mesh screen of the end of the suction tube, for the motor has a filter screen (in line) inside the motor housing and it is perfectly clean. When the motor seems to be running out of fuel, a few squeezes on the primer bulb brings it right back to life. Back to the VRO??

Badcrank 777
 
This is where I am at now. I installed all new hose & clamps. Also the reservoir is very clean and I pulled the unit out of the tank and filter was also very clean. The oil flows very freely and I purged the line of any air right up to where it connects to the VRO, with my helper squeezing just slightly on the bulb just until a little oil came out of the end of the hose, I admediatly connected it to the VRO and clamped it. Then started the engine with the fuel line plugged into my premix gas tank from the other boat, Started the engine and afterwards while running I gave the bulb one squeeze ONLY, and no alarms. I then switched back to the main gas tank (straight fuel) (non ethanol) and so far everything seems to be fine (no alarms)

One puzzling thing though, after the engine has been running for a while, it is running out of fuel in the line from the tank. I have all brand new hoses & clamps, there is no air leaks, I have teflon tape on all the fittings going into the gas tank and they are all tight. The suction tube in the tank has no restrictions, I even removed the wire mesh screen of the end of the suction tube, for the motor has a filter screen (in line) inside the motor housing and it is perfectly clean. When the motor seems to be running out of fuel, a few squeezes on the primer bulb brings it right back to life. Back to the VRO??

Badcrank 777
 
That is what I thought also, So I revisited the VRO, of which I rebuilt with the new purple colored air motor valve, and all the other OEM (Johnson) parts. I followed the step by step procedures and pictorial to a tee, that the " MasterTech Marine" out of Florida offers on his web site. But I still took it apart again and looked for any issue that I may have introduced on reassembling it. It's back on the motor now, but could not try it yet, for we had a storm come in, drop the temp to 7^ and snow. only one day worth, rest of the week back into the 60^ so will retry then and report back.

P.S. I also checked the housing for any cracks, wear etc. all looked very good. I also done the flow chart test for the VRO and the air motor was functioning as it should with no leak down.

Thanks,

Badcrank 777
 
If the cylinder that operates the VRO has proper compression and none of the leaf valves in the reed plate are broken, the pressure pulse to the VRO, needed to provide the VRO to function properly "should" be okay. You can check this simply by disconnecting that hose and checking the pressure with your finger while cranking the engine over. I suspect you've already checked this but it's worth mentioning.

You apparently are questioning the possibility that the VRO is faulty... and due to the cost of that overpriced ball of black plastic, that's understandable.

However, unless there is a air leakage point somewhere between that VRO and the bottom portion of the fuel pickup line within the built-in fuel tank, which if outside of the tank would also result in a fuel leak.... The fact that pumping the fuel primer bulb (acting as a manual fuel pump) causes the problem to cease points to a malfunctioning VRO.

In your wording, I'm unsure if you have already performed the following so I feel it's worth mentioning.

A final check would be to hook up a portable 6 gallon tank (whatever) with a good known hose, primer bulb, etc etc to see if that corrects the problem or not... and if not, that would point to a failing VRO as well.
 
Post # 32 suggests that another tank was tried.-----I am thinking there is an issue with crankcase compression to drive the VRO pump.-----Or check valves in VRO air motor are leaking.----Heck if you were in my area I could loan you one of a dozen or more VRO pumps to test run.-----But try test running with a " know to be good " portable tank and hose.----As always I think there is an easy way to find out what is wrong here.----Testing and more testing is needed.
 
Thank you so much for that very informative information. I did have connected a seperate fuel (portable) tank, with premix), when I was testing the new oil lines from the oil reservoir to make sure the oil pump in the VRO was working. and same issue presented itself, it was not sucking the gas after initial priming, only ran until there was no more fuel pressure to the float bowls.

And you are right! it is ridiculous what they want for a new VRO, it's just a little plastic and a hand full of rubber valves. I repeat again absurd the cost of a 40.00 dollar item. But I guess they think if you own a boat your a millionaire, which I am not. So I am trying very hard to do anything it takes from not purchasing a new VRO. But worse case scenario, if I am completely know 100 % it is a faulty VRO then yes I will bite the bullet.

I do have good compression )or so I think (95 psi equal on all four cylinders) and I did replace one of the reed valves. the rest and including the one I replace are all sealing very tight with no light through them when closed, even though I know a very small sliver of light would be ok.

I Did hook up a vacuum/pressure gauge to the pulse limiter port and it was swinging for 3 psi to 4hg, so I figured that was enough to run the air motor in the VRO.

I will be testing it again on Wen. since I when through the VRO for the second time.

Thank you all,

Badcrank 777
 
Yes I realize that, but at this point the oiling system seems to be working, but the fuel chamber seems to not be sucking the fuel properly from the tank. And I don't want to invest in a new VRO or non oiling one, until I am sure the VRO is the culprit. I should know on Wen.

Thanks
 
New report:

I now can start the engine, there are no alarms, and it runs. But this is a new development. It will run smooth at about 1500 RPM then I shut the "start idle" lever off, and it will set there and run, then idle way down and run ruff "loping" then after about 5 sec, speed back up all by itself and run smooth. Then after about 10 sec, it will idle back down by itself and start the ruff idle "loping" again. It will keep doing this over and over until I shut off the key.

Any input would be appreciated,

Thank's,

badcrank 777
 
When you say "case leak" do you mean the VRO case leak? The pulse from the crankcase is 3 psi to the VRO. Does anyone know for certain what the VRO pulse pressure from the pulse limiter should be? There seems to be a real lack of information concerning these numbers associated with the pulse limiter and or output of the fuel side of the VRO. For any type of testing these numbers would be most valuable in trouble shooting these engines. Without this info a person is just second guessing or shooting in the dark. And I for sure have no idea what they should measure.
 
Here is the problem with rebuilding VRO pumps. They are succesful about 1/2 the time and I would never trust the oil side after it is apart. You could put a standard fuel pump on and remove the VRO completely. 3 psi should run the VRO pump you need to remember it runs on the same pulses as the standard pump. It sounds like you have an air leak in the pump and are losing prime. And if the VRO is pumping oil you absolutely have enough pulse to pump fuel. You do not have a pulse problem.
 
The pulse limiter has nothing to do with the regular operating pressure of the VRO.------The pulse limiter is a FLOW FUSE and protects the VRO from high pressures.-----Should there be an event in the crankcase that generates a very high pressure / air flow to the VRO the pulse limiter CLOSES.----Due to the size and large surface area the VRO could explode !!!----The pulse limiter is an OPEN device that closes should there be a high air flow.----Simple stuff.
 
Thank you both, this clears up a lot of things for me. It's just I am new to this VRO system, and I have heard so many pro & cons about the system, it gets real confusing. I am going to shift my attention away from the pulse limiter, for like you say it would not even run or pump oil if there was an issue with no crankcase pressure. It's just that that VRO internally seemed so simple, that I just did not see any issue with rebuilding it, so few parts etc. but I am starting to lean towards that being my main issue. After finding that I had overlooked the "fast idle jets" being plugged up in the first place. It's just that 500.00 + for a new VRO hurts a little and did not want to go there if not necessary. So have been searching every other possibility, before biting the bullet.
 
The jets screwed into the carburetor bowl are the HIGH SPEED JETS called an " orifice plug " in the parts book.-----They meter the fuel with a calibrated hole.-------The 87 model V-4 has a spot on the intake manifold to mount a simple non mixing fuel pump.-----Likely available on line for a few coins ( chinaman made ) of course.-----Easy to mount and give this motor a good test run.--------Then decide on the big bucks on VRO replacement / repairs.
 
Thanks, raceone. That sounds like a good plan! and a viable one. If that proves out, I did find the replacement OEM 4 wire VRO at "MarineEngine.com" for 465.00, But makes sense to do the other cheap route first, and then if the engine performs well on "premix" then I will invest. Yes "high speed jets" I will get that through my head!:)

Thanks,

badcrank 777
 
Pumps are listed from as low as $10 / 12 online.----Cheap and easy test.----One I saw was listed as " high performance "-----So that is proof that the chinaman knows how to make / MARKET these pumps.
 
Ha ha, ah yes the good ole China goods, which is now 98% of everything we buy, in fact when you see "made in America" it's almost a shock!

Anyway, I order what seems to be an excellent 12v small low pressure electric fuel pump, self priming at (2.5 ~4 psi shut off pressure with a 30 GPH flow), paid 12.00 for it (yes made in china) They wanted 95.00 at "O'reilly's" (darn near the same thing (and Made in China) I call them O'smiley's for there smiling all the way to the bank on how there ripping everyone off. So for 12.00 I will see what happens by running premix and taking the VRO out of the loop.
 
badcrank 777 said:
Oh, could you tell me why?, I was just doing this to see if the motor ran ok, and if so was going to buy the new VRO
Click to expand...
Because if something happens there is no way that the pump automatically shuts off. If your carbs are not in perfect condition there is a good chance the electric pump overwhelms the floats or primer assembly. They are a fire hazard, that is why there are no carbed outboards out there with factory electric fuel pumps. . If you trim the motor far enough up you will be pumping fuel right out of the carb. And it will tell you nothing about the crankcase pulse which a cheap $12 mechanical pump will.
 
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Ok, thank you. It makes good sense what you say. So I will only use this pump I have coming strictly as a momentary test , all I want to do is see if the motor will idle without loping at idle then speeding up and cycling through this issue over and over again. And if does, then I will spring for a new VRO.
 
1993 Evinrude 100 XP.
After going through everything from fuel strainer, primer bulbs, filters, etc., what solved the problem was to replace and affix with metal hose clamps, the pressure hose from the lower front of the crankcase to the VRO/fuel pump. This hose provides the pressure to turn the VRO/fuel pump and had been leaking somewhere. It solved the problem IMMEDIATELY! Runs better than ever!
 
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