1996 Evinrude 50hp fuel problem- VRO pump??

duponts

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Mechanic tuned up engine last week (including changing the inline fuel filter which is the repair which I suspect may have caused my problem). When I started up the engine this weekend for the first time after the tuneup it stalled but I noticed it kept running if I kept squeezing the primer bulb. If I didn't squeeze the bulb the engine died (no gas) and sometimes the 'no oil' light and steady alarm went off. Upon closer inspection, it appears there is a small leak from the hose that connects to the fuel side of the VRO pump (there is some sort of black sleeve or fitting at the pump where it is leaking). I called the mechanic and he told me that he didn't believe that the VRO pump is bad because when I ran at 4000rpm I still had to squeeze the primer bulb the entire time to prevent the engine from stalling (he says that the pump usually doesn't just quit and, if defective, should work anyways at a high rpm but not at idle or low rpm). <br /> Any suggestions on what could be causing the problem? Could the small leak on the VRO pump fuel side be enough to cause this problem? I was also told by a boat parts store that they don't sell parts to the VRO pump and you must replace the entire assembly. Please help- I have a tournament to fish soon.
 

Dhadley

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Re: 1996 Evinrude 50hp fuel problem- VRO pump??

Welcome!!<br /><br />I think that some of the confusion come from the fact that that should not be a VRO pump. It should be an fuel / oil pump. It will pump at a straight ratio. <br /><br />That pump is the only thing that supplys fuel to the carbs automatically. When you manually squeeze the bulb you are by-passing the pump. So, we know the pump is not moving fuel by itself. Now, if there is a leak the pump will suck air easier than pull fuel. <br /><br />The first thing is to fix the leak. Hopefully that will cure the problem. If not then yes the pump can be bad and act as you describe.
 

duponts

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Re: 1996 Evinrude 50hp fuel problem- VRO pump??

Not sure what you mean when you say it should not be a VRO pump- it injects oil from a separate external oil tank that's connected to it- doesnt' that make it a VRO pump? I'm a newbie so sorry for my ignorance.
 

Dhadley

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Re: 1996 Evinrude 50hp fuel problem- VRO pump??

VRO stands for Variable Ratio Oiling. The theory was that at idle it was something like 150:1 and varied until 50:1 at wide open. <br /><br />Back in the early 90's they switched to a straight ratio pump that pumps basically 50:1 all the time. I believe the new pumps are called OMS pumps. Lots of problems were, and continue to be, wrongly blamed on the old VRO pumps.<br /><br />I'd hope that fixing the leak will fix your problem. If not, there should be parts available to repair your pump. Some techs choose not to work on the pump because of a perception of liability.
 

Brad Swygard

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Re: 1996 Evinrude 50hp fuel problem- VRO pump??

I have had a similar problem. my motor is older, an 80 something 40. At the botom of my VRO is the nipple that accepts the main fuel line. It has broken off now. Before I could not run at full speed but ok at half speed. Everyone told me it was junk in my high speed jets, which could be true, I have since cleaned them out. But when I went to see if this fixed the problem I could not even keeo my motor running. I then noticed fuel leeking out of the back of the motor. When I checked that nipple was completely broken. Could a crack there have caused an air suck that was my problem all along? When my father had the boat he decided to go back to mixing the oil in the tank, which has worked fine. My question now is can I just go around the useless VRO and send gas straight to the carbs, (thus less connections to suck air at)or does it function in some other way than mixing oil? BJS
 

Dhadley

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Re: 1996 Evinrude 50hp fuel problem- VRO pump??

There has to be a mechanical pump to supply fuel to the carbs. If the main fuel inlet is cracked it will suck air from there and you run the risk of the motor not running correctly and/or damaging the piston(s). <br /><br />If the fuel inlet is not replaceable then you need to replace that part of the pump or the whole pump.
 

Brad Swygard

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Re: 1996 Evinrude 50hp fuel problem- VRO pump??

Dhadley, is the VRO pump also the fuel pump? In other words the VRO does more than just mix the fuel? BJS
 
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