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Author Topic:   Diagnosing Electrical Problems With Pump Motors
bill4tuna posted 02-12-2010 12:11 PM ET (US)   Profile for bill4tuna   Send Email to bill4tuna  
I just need help and some follow-up. My 2003 Boston Whaler 2003 255 CONQUEST has a port and starboard [electrical pump motor for a waste macerator]. The rocker panel switch lights up but the pumps do not activate. [H]ow do I troubleshoot this?

Also, my [LOFRANS] windlass does nothing when [I] hit the foot switch or the hand switch at the helm. [N]o sound. [N]o click. [N]othing. [A]re these two electrical items connected? Please help .I want to solve the problem myself so I'll know what to do if this happens on the water.

thewayout posted 02-12-2010 01:13 PM ET (US)     Profile for thewayout  Send Email to thewayout     
First, your macerators. Obviously, you have power to the switch, as the indicator lights up. So put a meter on either the upper or lower terminal, press the switch either up or down, and see if you have power on either terminal. When you press the top half of the switch, that energizes the bottom terminal, and visa versa. Some might say check the breaker, but the feed to your switch goes through the breaker, and if the breaker was no good or tripped, your indicator wouldn't light up. Should you have power at both the upper and lower terminals, that points to the pumps. It is an unbroken wire between the switch and each pump, and it is unlikely that both positives have been compromised. More likely it is in the ground side, probably the grounds for the pumps are terminated to a ground [bus] in the bilge area. Put a meter from the ground [bus] to the negative batt terminal and check for continuity. If you have a good ground, your pumps are shot. Most macerator pumps are lucky to live 5 years, and Johnsons, which a lot of builders use, are lucky to live 2. One other thing, often macerator pump shafts get bound up by fishing line. However, when this occurs, the bound up shaft will cause the breaker to trip, which doesn't appear to be the case here.

Now, your windlass. Basically the same troubleshooting scenario. Do you have power at the switch? When you press up or down, do the corresponding terminals have power? You should have a solenoid behind the helm with a ground terminated to it. There should also be a ground [bus] behind your helm that also feeds the grounds on your switches. Since we know that [bus] is a good ground (because your switch indicators light up), check for continuity between the solenoid ground and the ground buss.

Of all small boat electrical [problems], 95-percent are ground [circuit] related. But as a boat gets older, equipment does [fail].

bill4tuna posted 02-12-2010 02:36 PM ET (US)     Profile for bill4tuna  Send Email to bill4tuna     
Thank you. I can do this, and will, on my next trip to the marina. Again, thanks. [W]hen you say "upper and lower terminal" exactly what are you referring to?
thewayout posted 02-12-2010 03:07 PM ET (US)     Profile for thewayout  Send Email to thewayout     
On a typical Carling rocker switch that is an on/off/on type, there will be 4 spade terminals on the back side. The uppermost one is the ground terminal, which allows the indicator light to operate. If the switch doesn't have an indicator light (like your horn switch), it won't have this terminal. The other 3 terminals are grouped closely together. The middle one is used to power the switch. The one above it is energized when you press the lower part of the switch. The one below it is energized when you press the upper side of the switch.
bill4tuna posted 02-12-2010 04:19 PM ET (US)     Profile for bill4tuna  Send Email to bill4tuna     
[T]hank you. [T]his lesson is not lost on me.
number9 posted 02-12-2010 04:33 PM ET (US)     Profile for number9  Send Email to number9     
You can find parts and wiring diagrams at
jimh posted 02-12-2010 07:40 PM ET (US)     Profile for jimh  Send Email to jimh     
Check for voltage present at the pumps themselves. If there is no voltage at the pump, work back towards the source of voltage until you find voltage.
thewayout posted 02-12-2010 11:38 PM ET (US)     Profile for thewayout  Send Email to thewayout     
Check for voltage present at the pumps themselves. If there is no voltage at the pump, work back towards the source of voltage until you find voltage.

Since there is an unbroken feed from the switch to the device, it is highly unlikely that both pumps have suffered the same demise due to a broken wire(s) in the feed.

I already addressed the source of voltage--the switch.

thewayout posted 02-12-2010 11:41 PM ET (US)     Profile for thewayout  Send Email to thewayout     
[Changed topic of discussion to the discussion itself. Article deleted. Sorry, we do not collect and organize articles where the topic of the article is the discussion itself or the website itself.--jimh]
jimh posted 02-14-2010 10:45 AM ET (US)     Profile for jimh  Send Email to jimh     
I would like to extend my apology to contributing advice here. I did not realize that offering advice would be closed once a concern had already been "addressed."

As for a switch being the source of voltage, I would disagree. The boat battery is the likely source of voltage, and the switch is just one of many places in the circuit path were the voltage is conducted to the load. That is why I made a suggestion to begin checking back from the load to the source to discover where the discontinuity in the circuit is occurring.

A wonderful aspect of investigating electrical problems is their compliance with the laws of Physics, and usually the cause of a problem in a simple DC circuit in which a source of power (a battery) is connected to a load (the pump) through a simple mechanical circuit control (the switch) can be rather easily detected.

thewayout posted 02-14-2010 07:00 PM ET (US)     Profile for thewayout  Send Email to thewayout     
[Another sidebar on the discussion itself as been deleted. Again, the purpose here is to collect useful information on the topic, and not to diverge into a discussion about the discussion itself.--jimh]

Note that the author stated his indicator light on his switch does indeed light up when the switch is activated, hence, the logical conclusion is that the switch has 12V power going to it. This does not mean that it has 12V on the output side, thus my instruction for testing for the presence of 12V on the upper and lower terminals when the switch is activated.

Once that had been determined, the problem obviously lays downsteam of the switch, which would be the pumps or the feeds. But, at that point, the switch is the "local" source of power. Yes, we all know the battery is the source of power, but I would like to think that the people I deal with in trying to solve their issues have a modicum of intelligence and therefore can determine that if they have power to the switch but no power coming out, it is the switch and not the battery that is the culprit. Once the switch has been determined to be "good", it is time to look downstream.

[More discussion about the discussion itself has been deleted.--jimh]

jimh posted 02-15-2010 09:35 AM ET (US)     Profile for jimh  Send Email to jimh     
Checking DC circuits with a multimeter can lead to some confusion if there are problems with the connections in the circuits. To measure a voltage with a meter draws only a small amount of current, typically only a milliampere or so, and if there is resistance in any connection in the circuit, the small current will not produce any significant voltage drop across that resistance. The actual load may draw much greater current, several thousand times more than the meter. At the operating current a resistance in the circuit will now have a significant voltage drop.

Also important is to check the return circuit to the voltage source from the load. Again, in a small boat the voltage source (or destination) is the battery negative. The circuit from the load to the battery negative also must be checked for discontinuity or bad connections.

As mentioned above, an estimation can be made of the likelihood that certain components would fail simultaneously. If several loads are found to be not working, it seems reasonable to estimate there is a low probability that all of the loads simultaneously and spontaneously failed. It is more likely that there is a problem in some other element of the circuit.

Using an in-circuit lamp as an indicator of voltage in the circuit can be useful, but be aware the lamp current is low and may be able to operate even if there were some resistance in the circuit. Also, more significantly, the lamp return circuit to the battery is likely different than the load return circuit.

Having worked with electrical and electronic circuitry for 50 years, I have found that describing circuitry in a narrative form is difficult, tedious, and seldom leads to clear understanding between writer and reader. I have also found that people who are skillful in diagnosis and identification of problems in electrical circuitry usually have a logical mind and a thorough understanding of the fundamental properties of electricity. Whether this can be imparted to a reader in a short narrative such as this remains to be determined.

bill4tuna posted 02-15-2010 01:22 PM ET (US)     Profile for bill4tuna  Send Email to bill4tuna     
This discussion is truly very helpful. Sitting in my shop I can lay out a 12 volt battery, a switch, and a load and follow the circuit and current. However, on this boat with the circuit not being "user friendly"(or that accessible), logic escapes me and I rapidly become helpless. This is what I am trying to overcome with this topic because there are those of you out there who can solve this through muscle memory. I, on the other hand, am trying to reduce "panic" on the water.
handn posted 02-16-2010 09:52 AM ET (US)     Profile for handn  Send Email to handn     
Previous posters are accurate about finding source of the problem. Let me suggest a shortcut for those of us intellectually challanged by wiring diagrams and those of us who consult the instructions only as a last resort.
I had three similar problems on my 305. In two of the cases the problem was at the switch and in the third case it was a short--easy to diagnose because the breaker popped off when the water pump was activated. For switch problems, try the following: first try switching the switch on and off on and off until it works or your finger gets tired. In a salt water environment, the contacts in the switch corrode but the switch may decide to resume working if exercised. (I had to do this with my winch several times because the winch switch was rarely used) If that doesn't work check the contacts to the switch. Take them off, use emery paper, dialectic grease, ect. If that doesn't work admit defeat, pull out the wiring diagram and the multi meter or in my case, call the mechanic.
I did have a freezeup in the macerator pump in one of my fish boxes. I noticed the water wasn't going down but I could hear the motor trying to work. I was able to "repair" the problem at least temporarly by rotating the pump manually.
Good luck!
seabob4 posted 02-17-2010 01:16 AM ET (US)     Profile for seabob4  Send Email to seabob4     
...pull out the wiring diagram and the multi meter or in my case, call the mechanic.

Hey, I can use the sidework.

Jerry Townsend posted 02-17-2010 08:34 PM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
And then - since both pumps are similarily affected - the problem will be something common to both pumps - like a bad switch - or a bad ground at the common ground point. Double check the ground for each pump and if that seems to be (or has been shown via using a multimeter) to be good, then the problem is in the switch. ---- Jerry/Idaho
jimh posted 02-18-2010 12:17 AM ET (US)     Profile for jimh  Send Email to jimh     
Another problem with electrical motors can be their starting current draw. Typically an electric motor will demand a very high current on start-up. This high current leads to high voltage drop across any resistance in the circuit. Once the motor gets running and at normal speed, less current is usually needed.

A motor attached to a pump can be affected by the load created by the pump. If the pump is heavily loaded and reluctant to turn, it can stall the motor, making it draw a lot of current. In the situation we are discussing here, there might be no problem at all in the electrical circuitry, and the real problem could be a couple of jammed pumps.

Jerry Townsend posted 02-18-2010 11:05 AM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
But Jim - both rotors jammed - or both motors/pumps "frozen-in-place" - ??? I don't think so. -- Jerry/Idaho
number9 posted 02-18-2010 04:34 PM ET (US)     Profile for number9  Send Email to number9     
I would not be so quick to assume both pumps didn't fail particularly since they are reported to be macerator type. A successful troubleshooter with a known good track record usually assumes zero.
seabob4 posted 02-18-2010 05:35 PM ET (US)     Profile for seabob4  Send Email to seabob4     
If a pump is "jammed", whether it be a macerator, bilge, FW, or "whatever", the current draw due to the pump trying to operate, as well as the thermal buildup, will cause the breaker(s) tripping. Since the same breaker(s) provide power to the switch(s), it is safe to say that this is not the case, as the indicator light(s) on the switch(s) would not operate as well.

Since Bill did not indicate that his indicator light(s) go out, it is safe to say a current/thermal overload from a jammed pump is not occuring...

On a side note, I am starting to see new macerator pumps that not only do not allow the ability to rotate the shaft with a flathead screwdriver to free up the shaft, they also don't allow dissasembly of the pump body to rotate it so that the discharge can be reoriented...

Guess when they get clogged, throw it away and buy another...

seabob4 posted 02-18-2010 09:49 PM ET (US)     Profile for seabob4  Send Email to seabob4     
I would not be so quick to assume both pumps didn't fail particularly since they are reported to be macerator type. A successful troubleshooter with a known good track record usually assumes zero.

You "assume" certain things...than you go about proving your assumptions wrong...

Just because fix #2 on a list of 5 fixes the problem does not mean you don't explore fixes 3, 4, and 5...

Jefecinco posted 02-19-2010 10:03 AM ET (US)     Profile for Jefecinco  Send Email to Jefecinco     
Recently both of my front porch lights stopped working. It was useful that I had a spare switch on hand so I replaced it. When I turned the switch on the lights did not work. Both bulbs, despite the odds against it, had failed around the same time.

I wish I hadn't thrown that bad switch away.


bill4tuna posted 02-19-2010 04:45 PM ET (US)     Profile for bill4tuna  Send Email to bill4tuna     
Well, I went to the boat yesterday with my multimeter and a test light. There was power to and from the switch. I could not reach the mercerator pumps to test them. I did find the negative bus plate with a mirror but could not reach them to clean them. They looked a little corroded in places. I think the problem is the negative wire of the circuit. I also checked the windlass motor. No power at the motor, no power at the relay. no action at the switch (which I did not have time to test)I tried the foot switch, no action. I suspect the problem is with the negative side of the circuit. While working on the boat in the slip I did catch 3 small corvina on fresh muscle. Catch and release.
Jerry Townsend posted 02-19-2010 08:18 PM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
Bill - you are getting there - and your problem, as you are tracking it down - is common to all of those components - which can only be a ground or not getting power. You will get there and fix your problem.

Now, having noticed corroded contacts - which increasingly draw more and more current - clean the areas up as well as you can - and then with the area cleaned and dried - cover the terminal/connector/et al. with a grease - or electrical grease to prevent further corrosion. There are probably articals in the reference section addressing this topic.

And hoping that Jimh forgives me for asking a non-related question - but as being from the intermountain area and only knowing trout, bass and salmon - what in the heck is corvina.

And addressing the previous discussion - as the probability of both motors/pumps failing simultaneously is only about 5 % and that of a bad switch or ground equally around 45 - 50 % - the first thing I would look at is the switch or ground and then the other. If that doesn't correct the problem, then the simultaneous failure of both pumps is then the cause - the only thing left.

And as Seabob4 points out - if the motors/pumps froze in place - the fuses would blow or circuit breakers trip like poste haste!! Thanks seabob4 - as that fact also went through my mind - and your bringing it up is good.

Jefecinco - realize that light bulbs, unlike motors and pumps, only last for a few hours (I have sometimes wondered if this life is not designed into the product to make us have to periodically buy more bulbs.). Perhaps both bulbs had been in service about the same time - or a voltage spike cause the failure of one or the other. I question your decision to replace the switch, given the relatively short expected life of standard light bulbs - and the relative cost of a couple bulbs versus the cost (initial and time) of installing a new switch. --- Jerry/Idaho

handn posted 02-24-2010 09:43 AM ET (US)     Profile for handn  Send Email to handn     
Forgive me for digressing off topic and responding to a question adressed to Bill4tuna.
A corvina is a warmer water, but not tropical, Pacific coast fish found in shallower water mostly over sand bottoms. The fish is exceptional eating and eagerly sought after by surf casters. They bite on plastic grubs and small spoons as well as bait.
Size up to 50 pounds although they are rare over ten.
If there were covina near where Bill4tuna's boat was moored, if I were he I would fish for them while the mechanic worked on the boat.
bill4tuna posted 02-28-2010 12:55 AM ET (US)     Profile for bill4tuna  Send Email to bill4tuna     
I will seriously consider your suggestion. You are indeed a sage..

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