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1996 Johnson 115 60 degree lower bearing failure

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  • #16
    Consider this question. Assuming that the motor now has the VRO fuel pump with just the oil injection disabled/capped and ran pre-mix only, why would it need another auxillary fuel pump that the original manufacturer never put on it?

    Putting an extra wrong fuel pump on top of another failing/weak fuel pump (VRO fuel pump unit) makes no sense, it is like using a vehicle to bumper push another vehicle that doesn't have enough power to accelerate and hold speed.

    Extra wear and tear for little gain.

    If the original VRO fuel pump puts the proper fuel output without leaks, then use it without that extra fuel pump.

    Other wise its buy OEM replacement VRO/OEM pre-mix only pump, or Mastertech's pre-mix only option.
    Last edited by havoc_squad; February 8th, 2019, 01:36 PM.


    • #17
      ??----Rust damage like that is NOT a result of exposure to the Florida air.-----It was submerged in my opinion !!----Also mechanical damage at one port.----The top cylinder on this motor is # 1 and the bottom is # 4


      • #18
        Thanks guys! I suspected as much. I will test the two VRO pumps I have (each powerhead) for 3 psi pressure tomorrow. Is there anything else I can do to ensure they are up to par? As far as VRO rebuild kit, I didn't see one here on Iboats. Is one available? Or, If I get to that point, am I just better off with the mastertech option. Prob won't go back to injection as I would need to source tank, lines and still have the worry of replacing a $500 pump.

        Yeah, I did notice that heavy damage to the port. It's amazing there wasn't a lot more to other cylinders as the bearings were everywhere. Submerging does fit. Thing that made me doubt it was that there was no corrosion on the outside of the powerhead or any of the electrical connections. carbs looks good as well. I guess a quick dunk is all it takes. if it was a non V would surely have thought head gasket.

        So is it that the numbering starts at top starboard as #1 and ends on bottom port #4. I see firing order 1234


        • #19
          ??-----The numbering has always been with #1 as the top cylinder and #4 is the bottom.------And why not take the VRO apart before jumping up and down and worrying about a kit / new pump.----There may be nothing wrong with it.----VRO gets blamed for everything because folks do not understand them..


          • #20
            Hey guys, definitely good advice on removing the dual pump contraption thing. Turns out, a second pulse line was never tapped. Whoever did this was just running gas through the VRO without a pulse. . As racerone suggested I took apart the pump that was on the bad motor, looked o.k. so back to stock (sort of- no oil injection). Two concerns though. That pump didn't have the oil pump part attached to the top of the pump. See photo. Looks like the center opening was capped. Was this modified, or was it off a commercial (premixed?) motor or something?? Is it ok to run this way?
            And when shifted to forward, the shift linkage pushes up against the pulse fitting. I guess that's the design, but with vibration, sure seems like a pulse hose air leak in the future

            Yup there I go worrying.


            • #21
              Looking at the parts diagram for a 1996 60 degree V4 115 HP model, the VRO style pump that has four, repeat four hose fittings is for the VRO pump that mixes oil and gas. (Fuel inlet, oil inlet, vacuum pulse, and outlet to vapor seperating Tank system.)

              However, BRP does make a VRO style pump (almost just as expensive as the one that does the oil/gas mixing) that is pre-mix only that has only THREE hose fittings. (Inlet, Vacuum pulse, and Outlet to Vapor Seperating Tank system.

              That is how you tell the difference between the VRO fuel pump that mixes the oil/gas and the VRO pump that does pre-mix only, by the number of hose inlets.

              By the way, it's not very hard at all to do a fuel pump demand test on the lake. Just takes time to plumb in a T fitting between the fuel pump and the Vapor separating tank.

              Extra fuel hose that is the size needed for the link between the fuel pump and VST.

              Insert an appropriate T fitting of the same fuel hose diameter size.

              Run a fuel line from that T fitting to the front of the outboard, then cap it off and clamp it down until you're ready to test the fuel pressure. Zip tie where appropriate to keep the hose manageable.

              Buy a step down adapter that will join your T'd temporary hose at the front of the outboard to a vacuum/fuel gauge hose.

              Use appropriate clamps to secure the fittings from leaks.

              Now you got access to doing a fuel pressure test with the engine cowl off on the water, at load at speed. You'll just need a helper driving the boat while you monitor the fuel pressure gauge.

              That may be overkill for your current circumstance if the service manual requires the following and your fuel pump/lines pass this:

              1. You should have X inches Hg. of vacuum or less on the intake side of the fuel line/pump with no bubbles.
              2. You have a stable X PSI at specified RPM level in gear, usually I believe that is about idle for most motors.

              However, if you experience any symptoms of leaning out only when getting close to WOT RPMs, expect that a fuel pressure test on the water at speed may be the only route.


              • #22
                Originally posted by racerone View Post
                VRO gets blamed for everything because folks do not understand them..

                So true. I guess it is easier and more profitable to sell a new pump, than to learn how it works and to do proper troubleshooting to find the real fault.


                • #23
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                  My pump does have 3 hose fittings. It had the 4 holes where the torex screws hold on the oil pump part that has the fourth hose fitting on my other Vro. Just not that part attached ,which is what confused me. I checked eBay and saw pumps that look like mine for premix. That is what I must have.
                  Thanks for taking the time to write all that info. A fuel pressure gauge does sound like a good idea, and def water doable.
                  The manual calls to do the vacuum test at full throttle. This is with the gauge connected to the fuel inlet. Definitely wouldn't want to do that out on the water.lol. Eventually I'll source a prop wheel as it seems like it would be handy for a lot of troubleshooting.