I need help... As a naval Architect, electrical issues are a mystery to me. I am a new Hunter 37C owner (1981 model) and very happy about our boat except that she fails to start after we have been sailing for several hours. I have replaced the batteries (3) and have one set up as a start and two as house batteries. Last time out the engine would not start on one, but did turn over and start on two. This week I left the boat off shore power and tried to start it - nothing. No alarms, no noise, nothing. I successfully and easily started the Yanmar diesel by jumping across the poles of the solenoid. Now all alarms function and it starts. I am baffled. I have checked switches, connections, fuses and wires. So smart Hunter owners, anyone have similar problems or anyone have a suggested solution???
Electrical Mystery
- Thread starter jayjenkins07
- Start date
Definitely a bad connection or switch, Jay. If switch on doesn't give you alarms when engine is not running, power is not getting to the panel and engine wiring, including the starter pushbutton.It is probably the hot wire in the bundle and probably one of the 3-4 push connectors in the wire run between engine and panel..
Solving electrical problems requires a methodical process and some basic understanding of electrical circuits. In your case that you present of a non-start issue, you need to understand that in order to start a diesel, you need everything in the starting circuit to be good. Sounds simple enough...
Write down results as you go along. Don't be surprised if the 'fault' is actually two or more lesser faults.
Where to start? Batteries first. Using your digital voltmeter you need to measure the voltage at the batteries. Fully charged you should measure 12.6 volts or more. Less than 12.5 volts means that your batteries are not fully charged. Since you successfully started your engine by jumping across the starting solenoid, I suspect that your batteries are fine.
Now attempt to start the engine. If it doesn't turn over at all you now are in the failure mode and you can effectively troubleshoot. Attach your meter directly across the starter motor (ground to the input wire). Watch the meter and attempt to start again. No voltage means that the solenoid is not being energized and that the problem is likely to be in the low power key switch circuit. A very low reading (under 8 volts) means that the solenoid is working but you have either bad connections somewhere in the high current path to/from the battery or the battery cannot supply the current to start. Next measure the voltage at the battery and attempt the start again. Seeing the same low voltage as you saw at the solenoid means that the battery cannot supply the current to start. If the voltage is a lot higher at the battery then you probably have one or more bad connections in the high current circuit.
If bad connections are indicated, check each connection for excessive voltage drop when you try to start. A good connection should drop no more than 0.1 volt.
If the problem is in the low power key switch circuit, you can verify this by running a separate test wire directly from the battery positive to the energizing terminal on the solenoid. If that action starts the engine, then the problem is a bad connection in the positive half of the start circuit. If it doesn't start, then run that test wire between the battery negative and the return at the solenoid. If it still doesn't start then you could have a bad connection in both the positive and negative circuits or a bad starter switch.
Effective troubleshooting requires you to gather all the clues about what works and what doesn't, and then deducing a scenario that fits all of the clues.
Write down results as you go along. Don't be surprised if the 'fault' is actually two or more lesser faults.
Where to start? Batteries first. Using your digital voltmeter you need to measure the voltage at the batteries. Fully charged you should measure 12.6 volts or more. Less than 12.5 volts means that your batteries are not fully charged. Since you successfully started your engine by jumping across the starting solenoid, I suspect that your batteries are fine.
Now attempt to start the engine. If it doesn't turn over at all you now are in the failure mode and you can effectively troubleshoot. Attach your meter directly across the starter motor (ground to the input wire). Watch the meter and attempt to start again. No voltage means that the solenoid is not being energized and that the problem is likely to be in the low power key switch circuit. A very low reading (under 8 volts) means that the solenoid is working but you have either bad connections somewhere in the high current path to/from the battery or the battery cannot supply the current to start. Next measure the voltage at the battery and attempt the start again. Seeing the same low voltage as you saw at the solenoid means that the battery cannot supply the current to start. If the voltage is a lot higher at the battery then you probably have one or more bad connections in the high current circuit.
If bad connections are indicated, check each connection for excessive voltage drop when you try to start. A good connection should drop no more than 0.1 volt.
If the problem is in the low power key switch circuit, you can verify this by running a separate test wire directly from the battery positive to the energizing terminal on the solenoid. If that action starts the engine, then the problem is a bad connection in the positive half of the start circuit. If it doesn't start, then run that test wire between the battery negative and the return at the solenoid. If it still doesn't start then you could have a bad connection in both the positive and negative circuits or a bad starter switch.
Effective troubleshooting requires you to gather all the clues about what works and what doesn't, and then deducing a scenario that fits all of the clues.
Thanks Rich! I will work through the process you have outlined. An interesting aspect of this problem is that when I am connected to shore power, everything seems to work fine. It is only when we have been sailing with no power for several hours, or I let the boat sit for days with no power that the failure mode occurs. We generally motor for 30-45 minutes to get into Lake Pontchartrain before we shut the engine down. I am confident that the batteries are good as they are brand new and were at 12.8V before I tried to start the engine today (after three days no charging or power applied). This is certainly helping me to get to know my boat better!!!
Starting Issues
Rich has sage advice. Your indispensable volt meter will help you get to the source of your problem. You can start at either end, the batteries or the starter. If your starter battery is fully charged, as Rich says, your meter should give you a solid 12.5 minimum at each connection. Be sure to test both sides; input and output.
I had a similar problem a few years ago when the windlass on our P42 would not work. I had to manually raise a 40 pound Danforth, with a 20 pound kellet and 50 feet of chain by hand.
To trouble shoot I started at the windlass and worked back to the house bank. Both sides of the foot switch, ditto the motor, solenoid and power panel circuit breaker; all were dead. Checked the battery bank and it was good. Now which of these wire goes to the windlass? As it turned out I had recently replaced the two 8D house batteries. Lots of wires working in a darkened area where I completely missed reconnecting the windlass power cable.
P.S. Solving the problem, as you say, helps you to get to know your boat. The rush from satisfaction reward is priceless when it comes to the boating experience.
Rich has sage advice. Your indispensable volt meter will help you get to the source of your problem. You can start at either end, the batteries or the starter. If your starter battery is fully charged, as Rich says, your meter should give you a solid 12.5 minimum at each connection. Be sure to test both sides; input and output.
I had a similar problem a few years ago when the windlass on our P42 would not work. I had to manually raise a 40 pound Danforth, with a 20 pound kellet and 50 feet of chain by hand.
To trouble shoot I started at the windlass and worked back to the house bank. Both sides of the foot switch, ditto the motor, solenoid and power panel circuit breaker; all were dead. Checked the battery bank and it was good. Now which of these wire goes to the windlass? As it turned out I had recently replaced the two 8D house batteries. Lots of wires working in a darkened area where I completely missed reconnecting the windlass power cable.
P.S. Solving the problem, as you say, helps you to get to know your boat. The rush from satisfaction reward is priceless when it comes to the boating experience.
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Good advice, but I suggest you start with the main engine ground wire. It's from the batteries to the engine, can't miss it. Then do what Rich said.
known weakness
Sometimes it is better to be lucky than good. There is a fuse on the port side of the engine that can get dirty or loose. This fuse feeds the engine panel in. Clean it, tighten it and your prob!ems may go away.
In any event, due to the fact that the solenoid draws 20 amps and the wiring size is marginal the engine sometimes won't turn over. Some owners have installed relays to get around the prob!em.
Sometimes it is better to be lucky than good. There is a fuse on the port side of the engine that can get dirty or loose. This fuse feeds the engine panel in. Clean it, tighten it and your prob!ems may go away.
In any event, due to the fact that the solenoid draws 20 amps and the wiring size is marginal the engine sometimes won't turn over. Some owners have installed relays to get around the prob!em.
All battery and panel connections do need to be gone over to insure future reliability, but Due to your being able to jump the solenoid and easily start the engine, i would say your immediate problem lies in the starter button circuit... either a bad button, a bad connection, or a bad solenoid.... sometims a solenoid can be bad and there wont be enough amps thru the start wire (either due to small wire or weak contact/connections) to engage the solenoid, but manually jumping it will do the trick....
If you had bad battery connections or engine connections (pos or neg) it wouldnt make much difference if you manually jumped the solenoid or not, cuz you wouldnt be getting the amps thru the main wires either way...
the main harness is connected to the panel and the engine wiring buy quick disconnect plugs....and they can corrode in the brass fittings and also where the wires are connescted to the brass in the respective sockets ...you could have a problem there as well...also the push button switch if you have one could be at fault ...but if you have a key switch to start the engine it could also be the culprit and that sounds like where you need to look as you said you could jump/hot wire the solenoid and get it running so check all those other things and test as you go buy pushing the start button or turning the key each time you service a connection and also check the ground wire in the harness first for corrosion ....i cleaned all my quick disconnect plugs contact cleaner and use dielectric grease on the connections....no problems now....good luck in the hut of your gremlins
Wow! I certainly appreciate all the good advice and help! I left the boat off shore power last night, hoping to recreate the "no-start" condition again. Went to start her up and bam - first time, no problems - the engine kicked right off and and started! Will let her sit a couple of days and try again so I can trouble shoot all the connections in the push button and key switches. Will also check all the wire connections again and make sure they are clean and corrosion free. You all ROCK!
I had a similar problem with my boat, I had sprayed some innox around the key switch and it would take lots of switches on and off before it would start so I sprayed it with electrical switch cleaner and fixed it. I also had the relay between the house & starter batteries start to work after a very rough trip down the coast. It hadn't worked since I bought my boat a year earlier meaning it didn't mater if the starter battery was switched on or off the boat started. I still always switched it off over night when anchored but this morning forgot to switch it on and it wouldn't start. So after starting it by shorting it across the solenoid made it into the marina, got the electrician out to discover all I had to do was switch the starter battery on. It's been 6 months and it is still working. Boats!
Well known problem
You need to install a small auxilliary relay which drives the solenoid.
This relay is energized by the key switch.
The harness wiring has voltage drops owing to corrosion, age, etc.
It makes energizing the solenoid from the key switch too critical.
The relay has a very low coil current, so it will easily energize with less voltage and lower current.
The relay contacts then energize the solenoid directly
As mentioned, this is well documented in the forums,
Do this, and your problem is gone.
This problem is well known, and has been documented many times on this forum. I had the same problem with my 40.5
You need to install a small auxilliary relay which drives the solenoid.
This relay is energized by the key switch.
The harness wiring has voltage drops owing to corrosion, age, etc.
It makes energizing the solenoid from the key switch too critical.
The relay has a very low coil current, so it will easily energize with less voltage and lower current.
The relay contacts then energize the solenoid directly
As mentioned, this is well documented in the forums,
Do this, and your problem is gone.
Do not discount the wiring harness from engine to cockpit panel. This harness was routed at factory through some bends around sharp fiberglass corners. With age and hull flexing this wiring will rub many times around those ages thus cutting into the harness, wire insulation and the wiring itself. It can cut through some of the wires and you will get random shorts on some of the sensors but once it cuts through the power wire the panel goes dead. On some boats it takes longer than others but this will happen. Pulling out the harness and visually inspecting it can usually lead to the location of such cuts. As to why you may get random occurrences it may be that the harness shifts in position but eventually it will fail. Having experienced such a failure your symptoms sound real close to a harness chaffing problem.
Re: Well known problem
Artboas - thanks for the input!! I searched the forum but obviously missed the right key words. Any details on the "right-size" relay or do I need to go to the Yanmar dealer for the relay and wiring diagram?
Artboas - thanks for the input!! I searched the forum but obviously missed the right key words. Any details on the "right-size" relay or do I need to go to the Yanmar dealer for the relay and wiring diagram?
any 30 amp relay will work like the one for your head lights on you auto...like this one http://www.ebay.com/itm/like/380980113871?lpid=82