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Johnson Raw Water Pump Installed on 6.2-gctid383255

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    Johnson Raw Water Pump Installed on 6.2-gctid383255

    What started me on this project was the overheat I experienced just prior to leaving home for the sound. I had just finished installing the new distributor cap, spark plugs and antifreeze when the temps shot up to 210* while on muffs. So the epic journey began... I thought I ate the impeller but that was not it (see photos below). I ended up being a frozen thermostat (more photos). Funny thing, it looked brand frekin new...Well, finally got her done. I had an overheat and thought it was the impeller. It was not. It was a stuck thermostat which I will address later. But once removed, the OEM raw water pump which has the air purge system nipples on it was worn out. The Merc dealer said he sees them wear out after as low as 250 hours. MSRP is about $658 for this pump plus another $38 for the impeller. BUT, they were on back order till 1 May (This was mid April when I started this quest). The back order quickly changed to mid June before they would even accept orders and it wasn't even May yet...I was having none of this sit well with me and got a recommendations to trash the air purge pump for one with out the nips, etc. But I saw Papa Charlie had installed the Johnson Pump on his engines and then I heard from Rick of Bounty fame to look at Johnson crank mounted pumps. Rick even sent photos and serial number info to help me out...Well, I did a ton of research and found that I could 'possibly' install one. First obstacle was to see if it could be a good replacement since my closed cool engine requires more raw water than the leg can provide. I have a separate seacock installed just for 1.25" the raw water pick up hose. The Johnson pump dealer in Seattle assured me that the F6B-9 would work well and move lots of raw water even though he never heard of one on a 6.2. Second obstacle was to see if the crank shaft pulley had clearance for a mounted Johnson pump. The 6.2 Horizon engine has a deep dish crank shaft pulley and I did not want to add spacers to mount the pump if at all possible. In the end, I did not. It barely cleared but like horse shoes and hand grenades, close is all I needed. Next challenge was what size serpentine belt would fit the 6.2 with the OEM pump missing? Found a belt that works fine (57807755Q05). I bought 10 feet of wire reinforced 1 1/4" hose, four #28 SS clamps and one 1.25" SS cushion clamp. The bracket for the Johnson pump was special order from Louisiana (Marine Engineering) and that took the longest time to get them to sell one for me. No one makes this bent piece of steel with mounting holes anywhere else in the world... BTW, the Volvo tube style bracket for the Johnson pump does not fit either.So, several weeks of frustration, from a stuck thermostat that started this to what I have now is priceless. Besides, I can now remove the impeller by pulling a plate off the front of the pump in about 4 mins and over long periods of non use, I can easily pull the impeller so the rubber does not set over winter. AND best of all, I can replace the entire pump for almost 1/3 the cost of the OEM pump... Adding MSRP of all the parts including the new thermostat (minus the antifreeze) would add up to $511.27. Finding all parts on line and locally would add up to ~$374.Engine runs at a constant 158* now...My only concern now is the pump seems to drift a tad when at low idle speeds but smooths out nicely at normal running speeds. The bracket has a hole that allows for this movement and is cushioned by a tall rubber grommet.First photo: bracket, second is the OEM pump removed, third is the OEM impeller, fourth is the inside of the OEM pump (note wear marks, it had 350 hours on it and last photo is the completed project.

    [img]/media/kunena/attachments/vb/686774=27818-bracket1.jpg[/img]

    [img]/media/kunena/attachments/vb/686774=27819-crank.JPG[/img]

    [img]/media/kunena/attachments/vb/686774=27820-impeller.jpg[/img]

    [img]/media/kunena/attachments/vb/686774=27821-pump.jpg[/img]

    [img]/media/kunena/attachments/vb/686774=27822-pumpinstall.JPG[/img]
    Doug ;}
    MMSI: 338068776
    "Go Aweigh to" Photos < click on red letters... 2001 Bayliner 2452 w/6.2 HO (paid for)


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    #2
    Looks like a super solution. Glad you are good to go. Does the pump come with its own pulley? I thought it was to fit on the crank shaft pulley.

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      #3
      No pulley required. It needs to clear the crank shaft pulley. The turning of the crank shaft turns the impeller inside the pump...
      Doug ;}
      MMSI: 338068776
      "Go Aweigh to" Photos < click on red letters... 2001 Bayliner 2452 w/6.2 HO (paid for)


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      Comment


        #4
        Go Aweigh2452 wrote:
        No pulley required. It needs to clear the crank shaft pulley. The turning of the crank shaft turns the impeller inside the pump...
        That is what I thought. Then why do you need a different belt?

        Comment


          #5
          2859er wrote:
          That is what I thought. Then why do you need a different belt?
          With the OEM pump gone, the serpentine belt does not have a pulley to go around. In teacher talk, The OEM Pump was completely removed from the equation.

          Thus I had to find a belt that was short enough to take up the 'slack' of not having a pulley in the loop. I could have left the OEM pump in the loop but eventually, the bearings may have failed due to side stress and no impeller inside to relieve some of that sideways stress. The OEM pump is not designed to run without an impeller and running it dry is not an option so I pulled the OEM pump...
          Doug ;}
          MMSI: 338068776
          "Go Aweigh to" Photos < click on red letters... 2001 Bayliner 2452 w/6.2 HO (paid for)


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          Comment


            #6
            Go Aweigh2452 wrote:
            With the OEM pump gone, the serpentine belt does not have a pulley to go around. In teacher talk, The OEM Pump was completely removed from the equation.

            Thus I had to find a belt that was short enough to take up the 'slack' of not having a pulley in the loop. I could have left the OEM pump in the loop but eventually, the bearings may have failed due to side stress and no impeller inside to relieve some of that sideways stress. The OEM pump is not designed to run without an impeller and running it dry is not an option so I pulled the OEM pump...
            Oh, I get it. Thanks for the explanation.

            Comment


              #7
              Doug, I am glad that this worked out for you. Looks like you have plenty of space for impeller R&R to boot! :coo-

              Question: as you no doubt saw, in addition to the three mounting bolts, the pump mounting flange has dowel alignment holes in it.

              Did your serpentine pulley have the raised dowel areas for indexing and aligning the flange?

              .
              Rick E. Gresham, Oregon
              2850 Bounty Sedan Flybridge model
              Twin 280 HP 5.7's w/ Closed Cooling
              Volvo Penta DuoProp Drives
              Kohler 4 CZ Gen Set

              Comment


                #8
                2850Bounty wrote:
                Doug, I am glad that this worked out for you. Looks like you have plenty of space for impeller &R to boot! :coo-

                Question: as you no doubt saw, in addition to the three mounting bolts, the pump mounting flange has dowel alignment holes in it.

                Did your serpentine pulley have the raised dowel areas for indexing and aligning the flange?

                .
                Raised dowel areas? The center of the crank shaft pulley has a center post that the Johnson pump slips over but that hole at the base of the Johnson pump is larger than that post and therefore, the pump has to be centered so the three bolts that hold it in place minimize the rotational play. There is limited play (rotational movement) around the center of the crank shaft so it looks a tad like it is not centered. The pump moves a tad like it is not centered while at idle which I think is the impeller making it look like it "sticks" but smooths out at normal running rpm... Is that what you mean?
                Doug ;}
                MMSI: 338068776
                "Go Aweigh to" Photos < click on red letters... 2001 Bayliner 2452 w/6.2 HO (paid for)


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                Comment


                  #9
                  Doug, this first image is the GM SBC V-belt crankshaft pulley. I'm not certain whether or not the serpentine crankshaft pulley offers these dowells.

                  Second image shows the three mounting bores..... these are equally spaced.

                  The larger dowell alignment bores are A-semetrical.

                  NOTE: the three mounting bolts alone can be used when bushings are installed.

                  Otherwise, the the three holes are slightly over-sized from that of the mounting bolt OD.

                  If your pump base flange is not dowell aligned to the crankshaft pulley, that may be part of your wobble!

                  Edit:

                  My mistake.... on some of these, there are actually four dowel alignment bores (green circles) in the mounting flange. See pic #3.

                  Attached files [img]/media/kunena/attachments/vb/688205=28077-Johnson-F6B-9 for Doug Cook 2 .jpg[/img] [img]/media/kunena/attachments/vb/688205=28038-Johnson-F6B-9 for Doug Cook.jpg[/img] [img]/media/kunena/attachments/vb/688205=28037-SBC crankshaft pulley.jpg[/img]
                  Rick E. Gresham, Oregon
                  2850 Bounty Sedan Flybridge model
                  Twin 280 HP 5.7's w/ Closed Cooling
                  Volvo Penta DuoProp Drives
                  Kohler 4 CZ Gen Set

                  Comment


                    #10
                    nice install doug, great work.

                    Comment


                      #11
                      I am very happy with my Johnson pumps. They were very easy to install as my pulley had the dowel pins. Mine was pre serpentine so I got to eliminate one belt.

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