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J70tlcrd fuel/VRO issue

S

steffco

New member
I have a new to me 84 70 that will not run much above an idle for very long in gear unless I pump the bulb, then it seems to run fine. Once it dies I can pump the bulb and it will start and run again even though the bulb seems fairly firm. From what i can see this engine has the first generation VRO with no wires and a black plastic elbow on top. I cant see the emitter and all the fuel hoses seem to be original blk. I have tried 2 different fuel supply systems and it makes no difference.
Am I cheating the engine of oil by pumping the bulb to keep it running at speed? I am not sure that the warning systems work due to some shady wiring but the motor seems to run fine and cool. Compression on all cyl is between 145 and 150. I do not have any pressure or vac gages on hand but can buy if need be.
What are my likely culprits?
Thanks
 
The VRO pump is very easy to take apart for inspection.-----So go ahead and do that.----Your cheapest option to do.----------You might want to try running with a known good portable tank and hose.
 
I did try the other tank with new gas trick and it ran the same as the built in tank. Do you think pumping the bulb just pushes fuel or does it push the motor/pump and move both oil and gas? I will work on it this weekend, thanks for the reply
 
You're describing a first generation VRO with no warning system.... 31 years old! It was a disaster, responsible for hundreds of blown powerheads!

In pumping the fuel primer bulb, you are acting as a manual fuel pump and you're simply pushing fuel (unmixed fuel) through the VRO to the carburetors. Until you solve this problem, mix the fuel you're using 50/1 or else you're going to destroy that engine.

You need to either replace that VRO pump or convert the engine back to the small regular fuel pump it used the previous year and mix your fuel as in past years.
 
In the process of changing the old VRO to a non vro pump I found most of the fuel line clamps and lines to be old and broken or cracked. I think the vro was working on the oil side just had a leak on the fuel side which is why it ran ok when I pumped the bulb. I found a local lower unit re-builder who sold me a like new OMC non vro fuel pump with a nice homemade bracket for $25. He had it on a powerhead that the last owner forgot to add oil to his fuel after he removed his VRO pump.
Everything works as advertised now! Thanks for all the help
 
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