# Any Advice? 70 hp Evinrude fuel problem



## jryno (Nov 8, 2007)

I've got a 1994 70 hp Evinrude that I rebuilt last fall. The engine starts easily, idles perfectly and runs smoothly most of the time. The problem is fuel delivery. When I pump the priming ball to full and firm, the engine runs great. After a minute or so, sooner if at higher RPM, I have to pump the ball to keep the engine at the same RPM. Without pumping the ball the RPM's drop and the engine will eventually die. I have new fuel lines, new fitting on top of tank, new oil/water separator, and new priming ball/hose combo. Priming ball fills with fuel easily so I don't think I have an air leak in fuel lines. I removed the oil injection oil lines, and unhooked the associated wires to the VRO side of the fuel pump. I premix the fuel now. The old oil lines into the VRO are still attached. With the oil side of the fuel pump disabled would or could air get sucked in through the oil lines and cause problems with the fuel pump?


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## oxbeast1210 (Jun 21, 2010)

did this issue just start happening or did it start after u went to premix?

Sent from samsung Galaxy note using Forum Runner


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## SHO-NUFF (May 30, 2011)

Plug the oil supply port on the VRO pump. They also make a Non VRO pump, Fuel only, if you ever have to replace it.


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## todd in the bay (Oct 3, 2007)

I HAD the same trouble with my 90 Johnson. It turned out to be a faulty primer bulb. Do you have another tank and line you could use? This would help identify the problem. I firsft added stanless hose clamps on the fittings, but then saw the gas flow back through the primer bulb so knew it was flowing in both directions, incorrectly. Changed out the bulb and fixed the problem.

Let us know if that works.


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## jryno (Nov 8, 2007)

oxbeast1210 said:


> did this issue just start happening or did it start after u went to premix?
> 
> Sent from samsung Galaxy note using Forum Runner


Not sure. The engine sat in my garage for three years before I rebuilt it last fall.


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## jryno (Nov 8, 2007)

SHO-NUFF said:


> Plug the oil supply port on the VRO pump. They also make a Non VRO pump, Fuel only, if you ever have to replace it.


I figured that I should do that. Where can I find a plug? And yes, a new pump is $400 or so. Slightly cheaper w/o VRO.


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## jryno (Nov 8, 2007)

todd in the bay said:


> I HAD the same trouble with my 90 Johnson. It turned out to be a faulty primer bulb. Do you have another tank and line you could use? This would help identify the problem. I firsft added stanless hose clamps on the fittings, but then saw the gas flow back through the primer bulb so knew it was flowing in both directions, incorrectly. Changed out the bulb and fixed the problem.
> 
> Let us know if that works.


Thanks. If plugging the VRO side of the pump doesn't work I'll try a new primer bulb. Were you able to pump yours up firm when it was bad?


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## SHO-NUFF (May 30, 2011)

jryno said:


> I figured that I should do that. Where can I find a plug? And yes, a new pump is $400 or so. Slightly cheaper w/o VRO.


Think the oil line is 5/16. Cut about an inch of hose off and stick a bolt in to make a plug. Try the auto parts store for a cap that will fit the nipple on the pump.


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## jryno (Nov 8, 2007)

Thanks Sho-nuff. I appreciate the help.


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## Sequoiha (Sep 28, 2007)

It appears you have a bad fuel pump, it is pulse operated from the crankcase, and is encased in the vro. could just be the diaphram. i have replace several of them over the last couple of months..


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## SHO-NUFF (May 30, 2011)

Ethanol related failures??


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