Forums General Discussion Large resistor/fuse/circuit breaker on W60

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    • #68295
      Seawater
      Participant

      My W60 has a large resistor looking thing between the batteries and the starter. It is on the port side near the transmission. Does anyone know what this thing is for?

      My engine has never cranked over very well, always grinding over slowly even with new batteries with a fresh charge. I have heavy 00 or 000 welding cable to the engine and a good ground.

      Today I bypassed it, and the engine cranks like it ought to, and starts much quicker than it did.

      Any help would be appreciated.

    • #76953
      petedd
      Participant

      Sounds like a fuse. If you remove it, put an appropriately sized
      switch in-line. If you have ever had a starter stick, you know that it
      can start a fire in pretty short order so having a way to disconnect the
      circuit should be available.

      Pete

      On 3/30/2011 8:26 PM, Seawater wrote:

      My W60 has a large resistor looking thing between the batteries and the starter. It is on the port side near the transmission. Does anyone know what this thing is for?

      My engine has never cranked over very well, always grinding over slowly even with new batteries with a fresh charge. I have heavy 00 or 000 welding cable to the engine and a good ground.

      Today I bypassed it, and the engine cranks like it ought to, and starts much quicker than it did.

      Any help would be appreciated.


      Walter
      SV Madness
      P424 Hull #1

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    • #76954
      Seawater
      Participant

      Thanks, I have never had that unpleasant sounding experience, and hope not to.

      I was looking for some other info last night and found a part number for a shunt resistor. It does make sense that since I have a ammeter (non- functional, replaced by link 2000 system) that ammeter would have a shunt. It could also act as a fuse.

      Also, there are two push buttons next to this think on the engine, that I think are some sort of circuit breaker for the starter, I have a vague recollection of one of them popping once, and it took a bit of trouble shooting before I pressed one ot the buttons and restored the desired function (cranking, as I recall). Maybe they use the shunt resistor to measure the current flow too, but I don’t know how they would interrupt the current if they are not in series with the power flow. And, why would there be two?

      Sweet mysteries of life.

    • #76955
      quent
      Participant

      Hi Walter-
      We have a W-58, not a W-60, but they are probably wired in a similar manner.
      The device with a button is a circuit breaker for the glow plugs. The other device is probably a relay for the starter solenoid circuit. This is required so that the current necessary to engage the starter does not have to go through the key switch or starter button. It could be that one of the connections is not good, and there is insuffient power to fully close the starter solenoid. I’d clean up all these connections and see if that fixes the problem. If that doesn’t work, replace the relay.
      ABYC and Coast Guard do not require or recommend fusing the starter cable because of the necessity to always be able to start the engine. However, the starter should be wired through the main battery switch to allow this circuit to be disconnected. I also fuse the battery bank at a level to protect this unprotected starter cable. I think I have a 500 amp fuse there, which has never blown.
      Regarding the use of welding cable for the starter, Pearson did this on our boat too. Welding cable is inadequate for engine spaces. The insulation will not stand up to oil, fuel, or the engine room temperatures. On Clairebuoyant, the insulation on the red starter cable softened and split lengthwise near the starter. Had the bare conductor touched the engine, we could have lost the boat to fire.

      Quent
      Clairebuoyant, #132

    • #76956
      petedd
      Participant

      On my w58 there were two breakers. One for the starter solenoid and one
      for the glow plugs if I remember correctly.

      On 3/31/2011 5:12 AM, Seawater wrote:

      Thanks, I have never had that unpleasant sounding experience, and hope not to.

      I was looking for some other info last night and found a part number for a shunt resistor. It does make sense that since I have a ammeter (non- functional, replaced by link 2000 system) that ammeter would have a shunt. It could also act as a fuse.

      Also, there are two push buttons next to this think on the engine, that I think are some sort of circuit breaker for the starter, I have a vague recollection of one of them popping once, and it took a bit of trouble shooting before I pressed one ot the buttons and restored the desired function (cranking, as I recall). Maybe they use the shunt resistor to measure the current flow too, but I don’t know how they would interrupt the current if they are not in series with the power flow. And, why would there be two?

      Sweet mysteries of life.


      Walter
      SV Madness
      P424 Hull #1

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    • #76957
      quent
      Participant

      Hi Pete-
      That would probably be a good idea. The Westerbeke wiring diagram shows one 20 amp breaker servicing both the glow plugs and the starter circuits.
      Quent

    • #76958
      RichCarter
      Participant

      I think it’s the shunt resistor for the ammeter. It should be between the alternator and starter. The batteries should connect to the starter, not alternator.

      Rich

      On Mar 30, 2011, at 10:26 PM, “Seawater” wrote:

      My W60 has a large resistor looking thing between the batteries and the starter. It is on the port side near the transmission. Does anyone know what this thing is for?

      My engine has never cranked over very well, always grinding over slowly even with new batteries with a fresh charge. I have heavy 00 or 000 welding cable to the engine and a good ground.

      Today I bypassed it, and the engine cranks like it ought to, and starts much quicker than it did.

      Any help would be appreciated.


      Walter
      SV Madness
      P424 Hull #1

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    • #76966
      Seawater
      Participant

      Thanks, all.

      It was indeed a shunt resistor for the ammeter. I don’t see the reason for passing the starter current through the resistor, so I am bypassing it.

      Thanks for the heads up on the welding wire. I used the term loosly to mean 00 fine stranded wire. I will have to see if it is marine graded.

      The circuit breakers seem to be for the pre-heaters and the alternator, but I have not confirmed.

    • #76967
      madsailor
      Moderator

      Hi Walter,

      The reason the shut is there is because on a normal engine installation all
      power is tapped from the starter. Marine installs are different in that
      there are two main circuits, engine and ship’s power. For true current
      draw, move the shut to a single ground point. Otherwise, move it to the
      line that powers the dc panel.

      The shut should have very little resistance. Negligible when considering
      ship’s loads.

      Bob

      I’m not being terse. This is from my mobile.
      On Apr 1, 2011 8:09 AM, “Seawater” wrote:

      Thanks, all.

      It was indeed a shunt resistor for the ammeter. I don’t see the reason for

      passing the starter current through the resistor, so I am bypassing it.

      Thanks for the heads up on the welding wire. I used the term loosly to

      mean 00 fine stranded wire. I will have to see if it is marine graded.

      The circuit breakers seem to be for the pre-heaters and the alternator,

      but I have not confirmed.


      Walter
      SV Madness
      P424 Hull #1

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    • #76968
      john stevenson
      Participant

      If indeed the shunt is producing significant resistance on the starter
      circuit, it must be defective. As Bob wrote, the resistance should be
      negligible, unless the shunt is broken (or it really isn’t a meter shunt).
      I’d just throw it away.

      On Fri, Apr 1, 2011 at 9:04 AM, Robert Fine wrote:

      Hi Walter,

      The reason the shut is there is because on a normal engine installation all
      power is tapped from the starter. Marine installs are different in that
      there are two main circuits, engine and ship’s power. For true current
      draw, move the shut to a single ground point. Otherwise, move it to the
      line that powers the dc panel.

      The shut should have very little resistance. Negligible when considering
      ship’s loads.

      Bob

      I’m not being terse. This is from my mobile.
      On Apr 1, 2011 8:09 AM, “Seawater” wrote:

      Thanks, all.

      It was indeed a shunt resistor for the ammeter. I don’t see the reason

      for
      passing the starter current through the resistor, so I am bypassing it.

      Thanks for the heads up on the welding wire. I used the term loosly to

      mean 00 fine stranded wire. I will have to see if it is marine graded.

      The circuit breakers seem to be for the pre-heaters and the alternator,

      but I have not confirmed.


      Walter
      SV Madness
      P424 Hull #1

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      Regards,
      John Stevenson
      http://www.svsarah.com
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