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Alternator tested works - still low volts on dash-gctid359935

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    Alternator tested works - still low volts on dash-gctid359935

    I removed the alternator, and had it tested - all OK. is 1995 2452 with mercruiser 350 bravo II. Isn't the regulator integrated into the alternator? Still 11-12 volts on dash voltmeter and I am trying to chase down what the issue is.
    cglazier - "Fiftybucks"
    1995 2855 7.4 bravo II

    #2
    You need to get a digital volt meter (cheep at Wallmart}, First check the batteries to be sure they're up to 12.5+ or so. Then check under the dash to make sure the reading is correct. The factory gauges can be off. There is a main heavy red wire feeding the fuse block. If the volts are still low there with the digital meter you might have a bad or loose connection back at the other end or the switch. Take the meter to the batteries and start testing the circuits for voltage at places like the main breaker on the engine and trim tab pump If its good keep testing and move forward till you find the drop. A wiring diagram is available online it will make the search easier.
    Carl
    2452

    Comment


      #3
      Like Carl says, the dash volt meter is just a rough guide. Almost everyone I've seen have not been accurate, Check the voltage on the back if the meter with a real voltmeter. Then work your way back down the wire harness. My guess is that the voltage on the back of the dash meter will be correct.



      I installed this digital gauge with a switch to check the 2 battery banks. My dash meters always show about 2 volts low compared to the digital one.

      Comment


        #4
        Agree.... the helm volt meters are rarely accurate.

        To test your charging system, your reading needs to be taken directly from the battery bank that is currently being selected via the MBSS.

        .
        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


          #5
          Fiftybucks wrote:
          I removed the alternator, and had it tested - all OK. is 1995 2452 with mercruiser 350 bravo II. Isn't the regulator integrated into the alternator? Still 11-12 volts on dash voltmeter and I am trying to chase down what the issue is.
          I get a lower voltage at the dash of my 2452 than at the batteries and always did (11.5 v) . . . . .It also creeps up when the engine has been running a while (I guess the batteries are probably reading 14v - if read across the terminals).

          I thought it was due to the original wiring getting corroded internally so I ran an extra fused power line to the dash and that also dropped a volt along its length as well NB I did use proper fat marine wire not automotive rubbish.

          I don't think you have anthing to worry about, it is just the volt drop along a very long piece of wire. Be aware that the total electrical path is twice the measured length as there is a "hot" and "earth" wire which both have resistance. Go find something else to worry about unless turning a load on causes even more voltage drop and your electronics won't work (that may be symptomatic of a bad connection). My Navman electronics turn off automatically at 10.5 volts. I suspect this is the lowest tolerable dc voltage for the kit. So, a full 11.5 v is a bonus.

          NB You can always test this out by "jumpering" directly from the battery to the dash.

          While I am thinking of it, the dashboard feed goes from the starter motor electrical block through to the dash. That is one oily filthy, hot area and subject to vibration. When you take your starboard manifold off for replacement sometime make sure all is well down there. I couldn't explain how bad my connector was when I replaced it when I did my manis last time.

          Terry
          Terry (Retired Diving Instructor and Part Time IT Consultant)
          1998 Bayliner 2452. 5.7l V8 - Edelbrock 1409 4bbl - Alpha1Gen2 - Solent UK.
          MMSI 235061726

          Comment


            #6
            I had a similar issue last summer and a friend suggested to check the multi pin junction on the wiring harness at engine. It showed a little corrosion and I put some contact grease on all the pins and he showed a trick that they use in the telecommunications industry, plug and unplug 3 times and then seal it up. Just like that I found the 2 volts that were missing. There will some line loss this heped me, worth a look.............
            2005 2359 Trophy Pro "SOLD"
            "Amigo"
            B lll 5 ltr.
            1998 2452 (Sold) "Island Time"

            Comment


              #7
              I have found that the ground gets overlooked. Remove and clean the main ground at the block. All pin connectors should be pulled apart and inspected cleaned and a shot of some sort of electrical cleaner or grease added before reinserting the pin connectors.

              Also because a wire looks good from the outside doesn't mean they are not green and corroded under the insulation, believe me i have seen to many to take for granted any wire on a boat.
              Be good, be happy, for tomorrow is promised to no man !

              1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

              '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

              Manalapan N.J

              Comment


                #8
                Chief Alen wrote:
                I have found that the ground gets overlooked. Remove and clean the main ground at the block. All pin connectors should be pulled apart and inspected cleaned and a shot of some sort of electrical cleaner or grease added before reinserting the pin connectors.

                Also because a wire looks good from the outside doesn't mean they are not green and corroded under the insulation, believe me i have seen to many to take for granted any wire on a boat.
                I agree a lot with Chief. A bad ground can be one of the easiest things to rule out, but, possibly fix a large number of electrical problems. I fixed my groud on the fuel sending unit, now the gauge works. Fixed the ground on my battery one day while on the water because my motor would not turn over. I also had issues with my radio.... yep, it was the ground.

                I would first check with a digital volt meterat your dash, just to make sure you are not getting false info from your dial.

                Comment


                  #9
                  Buy a digital voltmeter. 20-25 will get one good enough.

                  Read these:

                  http://www.baylinerownersclub.org/fo...ad.php?t=36592

                  http://www.baylinerownersclub.org/fo...ad.php?t=36593

                  I wrote them to help guys like you troubleshooting. I have troubleshooted electrical/electronic circuits all my life as my daytime job.

                  Then go for it.
                  Captharv 2001 2452
                  "When the draft of your boat exceeds the depth of water, you are aground"

                  Comment


                    #10
                    Most often it's due to voltage drop on the buss. If you want them to be more accurate, take a dedicated line back to the alternator and a dedicated ground back to the battery. The gauge alone will hardly care about line drop then.
                    Custom CNC Design And Dash Panels

                    iBoatNW

                    1980 CHB Europa 42 Trawler- "Honey Badger"

                    Comment


                      #11
                      Had the exact same issue, poor connection at the fuse that supplies power to the gauges, while someone is watching the gauge wiggle the fuse in the fuse box that goes to the gauges and see if the gauge moves up and down.

                      Comment


                        #12
                        [img]/media/kunena/attachments/vb/665318=25565-AlternatorConnector.jpg[/img] Thanks to all that provided such great guidance.I purchased a digital volt meter and hooked up to batteries.. it was only 11-12, then tested at the back of the voltmeter... 11-12. was bad... I took the alternator back out and down to a second shop.. tested at 80amps and 14 volts, I saw the test just so i knew for myself.I looked at the bus, pulled every fuse, re-tightened the connectors with the brass screw heads.The big red connector to the alternator... actually fat orange w/red stripe, was corroded and then soldered and put back on.. NOW 13.5 VOLTS ON Dash Voltmeter!!Thanks all !! At last I feel like I can drive down the lake for more than 1 hour and make it back!
                        cglazier - "Fiftybucks"
                        1995 2855 7.4 bravo II

                        Comment


                          #13
                          That is one nasty looking connector / wire. I have a few of those on my boat as well, and should get around to replacement. I suspect there are more and will show themselves over time, but I'd rather head off potential problems. Here is a pretty informative link about wiring:

                          http://www.pbase.com/mainecruising/wire_termination

                          and the main page:

                          http://www.pbase.com/mainecruising/boat_projects

                          I may have even got this reference from here!

                          Comment


                            #14
                            Another satisfied customer.
                            Be good, be happy, for tomorrow is promised to no man !

                            1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

                            '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

                            Manalapan N.J

                            Comment

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