Boater Sam
Well-known member
you only need to flash it, reaction will be instant if it is working.
Bukh DV20 starter motor not working. Any suggestions?
- Thread starter joyfull
- Start date
Juan Twothree
Well-known member
Firstly, if you have a multi meter (or 12v bulb on wire) check if there's voltage with the key turned, to the start terminal on the solenoid. If there is, short out the two large battery connections on the solenoid (an old spanner works) and see if starter motor turns.
This proved very effective when we got called out to a becalmed yacht last year.
Saved us having to tow him a long way on a very hot day.
joyfull
Member
Does the key have to be turned to make this work or just upright with ignition light on?
James_Calvert
Well-known member
I don't think it matters what position the ignition key is in for the purposes of the test. But if the test worked, and you wanted to use the same technique to bodge start the engine, the key ought to be in the ignition on position. And you would disconnect the bodge as soon as it started, just like you release the ignition key.
My daughter had a diesel car which she often had to start this way, had a bit of wire already connected which she just had to touch the other terminal with. We had a car with a more permanent arrangement involving a toggle switch.
Neither really suitable for boating though!
My daughter had a diesel car which she often had to start this way, had a bit of wire already connected which she just had to touch the other terminal with. We had a car with a more permanent arrangement involving a toggle switch.
Neither really suitable for boating though!
joyfull
Member
I managed to check the ignition switch with a multimeter to the blue wire that bayonets onto the back of the solenoid and am getting the full 12.6v from the battery.
Tried to jump between the two nuts (see pix) on the back of the solenoid and no response at all. I was expecting sparks!
I am thinking that either 12.6v is not enough to activate the starter motor or the solenoid is jammed (the starter motor cog turns fine).
If anyone has a Bukh starting handle in the Plymouth area that I could borrow would be much appreciated.
Tried to jump between the two nuts (see pix) on the back of the solenoid and no response at all. I was expecting sparks!
I am thinking that either 12.6v is not enough to activate the starter motor or the solenoid is jammed (the starter motor cog turns fine).
If anyone has a Bukh starting handle in the Plymouth area that I could borrow would be much appreciated.
Boater Sam
Well-known member
OK we will try again. Have you 12v on the big terminal with 3 connections on? If you flash a wire from this to the tag that the blue wire is on, what happens?
If you have 12v on that big terminal the solenoid should pull in.
If you have 12v on the big terminal and shorting it to the other big terminal does nothing then you have either a duff starter or a terrible battery or earth lead connection .
If you have 12v on that big terminal the solenoid should pull in.
If you have 12v on the big terminal and shorting it to the other big terminal does nothing then you have either a duff starter or a terrible battery or earth lead connection .
joyfull
Member
Ok. I will check the terminal with the plus sign.
Bilgediver
Well-known member
The best way is to short the Blue to the big terminal with more than one cable furthest from the engine.
If you short the two big ones and you have a pre engage type starter shorting the two big terminals will spin the starter but not start the engine.
If shorting the blue to the big outer produces no result or noises then the solenoid could be burnt out or have a faulty internal connection. These solenoids are available from local motor factors for far less than marine suppliers.
If you suspect a duff earth then clip a battery Jumper/ Booster lead from the battery negative to the alternator starter. I have seen earth/ negative connections on the engine appear fine visually but with corroded contact surfaces.
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joyfull
Member
I have borrowed one of those battery booster boxes. No activity when I attached to the battery with the Battery showing over 13v.
Could I test the solenoid/ starter by attaching this direct to the solenoid to see if it turns the starter. Box says 2000A.
Could I test the solenoid/ starter by attaching this direct to the solenoid to see if it turns the starter. Box says 2000A.
Boater Sam
Well-known member
Yes. Then connect the tag that the blue wire is on as well to the positive.
joyfull
Member
Do you mean I can connect the power box positive to the outside (marked +) and the negative to the bolt next to the engine. Then add a wire from the positive bolt to the tag that the blue wire (from the ignition switch)?
Boater Sam
Well-known member
NO! That would short the battery out if the solenoid was activated, not a good idea!!!!
Positive to the large terminal with 3 connections on, Negative to the engine block, anywhere solid metal, then connect the tag that the blue wire was on to the positive,
Positive to the large terminal with 3 connections on, Negative to the engine block, anywhere solid metal, then connect the tag that the blue wire was on to the positive,
joyfull
Member
Ok. Thank you!
VicS
Well-known member
Be warmed that a digital multimeter takes so little current that it can give a normal reading even through a bad connection.
A 12 volt bulb on a couple of leads is a better and more reliable way of doing this sort of test because it takes some current and will glow only dimly if there is bad connection. I (now) use an old car headlamp bulb with one good filament. It doubles up as a 12 volt lead lamp when necessary
A digital multimeter will make a fool of you sooner or later ............... been there, got the T shirt.
joyfull
Member
I am still struggling to find the problem. Access to the terminals on the solenoid is hopeless, so I am still unsure if it is electrical or mechanical problem.
I presume that it is unlikely that both the starter motor and the solenoid are both not working. So how can I check if it is one or the other (or back to the wiring)?
I presume that it is unlikely that both the starter motor and the solenoid are both not working. So how can I check if it is one or the other (or back to the wiring)?
Boater Sam
Well-known member
Sorry pal but we have told you several times how to do this, please read back through the thread and try following what you have been told.
If you are unsure or unable please seek professional help before you do some damage.
If you are unsure or unable please seek professional help before you do some damage.
James_Calvert
Well-known member
I think you've already had all the useful advice here and there.
But starting with the mechanical side...
You've said you can turn the flywheel. I didn't understand what you said about the cylinders. There's a linked pair of decompression levers on the top of the engine which you pull towards you to decompress, I assume you had to do that to be able to turn the flywheel.
There's a toothed ring on the flywheel which the starter motor cog engages when it's working. You said the cog is not jammed and turns fine. (It shouldn't be engaged with the flywheel teeth except during the starting process)
On the face of it then, if you can turn it over by hand, there's nothing mechanically wrong with the engine which would prevent the starter motor turning it over.
On to the starter motor. The electrical test for that is to short out the two big terminals, expect sparks as you do this, and the starter should spin up, the cog will go clunk into the flywheel and, if the battery and connections are good, the engine will turn over.
I guess you haven't got good enough access to do this confidently and safely.
You could take the alternator off to improve access, but I'd try other tests first.
You test the solenoid by energising the small terminal. You said you've done this and nothing happens. If it was working at all you would hear a click. I don't know whether that inevitably means it's working properly, but you could test this electrically by putting a voltmeter across the two big terminals. There should be zero volts across them when the solenoid is energised, otherwise 12v. Maybe that wouldn't be too difficult to check using crocodile clips?
You mentioned you'd been on a long run before the problem occurred. Something electrical may have got disconnected?
But starting with the mechanical side...
You've said you can turn the flywheel. I didn't understand what you said about the cylinders. There's a linked pair of decompression levers on the top of the engine which you pull towards you to decompress, I assume you had to do that to be able to turn the flywheel.
There's a toothed ring on the flywheel which the starter motor cog engages when it's working. You said the cog is not jammed and turns fine. (It shouldn't be engaged with the flywheel teeth except during the starting process)
On the face of it then, if you can turn it over by hand, there's nothing mechanically wrong with the engine which would prevent the starter motor turning it over.
On to the starter motor. The electrical test for that is to short out the two big terminals, expect sparks as you do this, and the starter should spin up, the cog will go clunk into the flywheel and, if the battery and connections are good, the engine will turn over.
I guess you haven't got good enough access to do this confidently and safely.
You could take the alternator off to improve access, but I'd try other tests first.
You test the solenoid by energising the small terminal. You said you've done this and nothing happens. If it was working at all you would hear a click. I don't know whether that inevitably means it's working properly, but you could test this electrically by putting a voltmeter across the two big terminals. There should be zero volts across them when the solenoid is energised, otherwise 12v. Maybe that wouldn't be too difficult to check using crocodile clips?
You mentioned you'd been on a long run before the problem occurred. Something electrical may have got disconnected?
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joyfull
Member
Thank you all for your patience.
Access is the problem. No side hatch and no rear access so very difficult even with alligator clips to test either the starter motor or the solenoid.
I will get an engineer to check now as the next move would be to remove from the engine and bring ashore.
Access is the problem. No side hatch and no rear access so very difficult even with alligator clips to test either the starter motor or the solenoid.
I will get an engineer to check now as the next move would be to remove from the engine and bring ashore.
James_Calvert
Well-known member
Do let us know what the problem is, hopefully probably something simple.
joyfull
Member
I suspect it will be wiring. We shall see. I will let you all know.
Thank you all again for kind and helpful advice. Much appreciated.