starting problem, isolator switch?

[TaffyRon]

Ive got 4 leisure batts, 1x starter, 2 big blue sea isolator switches.

the starter has a built in coil but wont start off the key, it was fine one night, next day nothing, starter tested thats fine, batts fine the only way to start the boat is with a jump pack accross the 2 points on the starter motor, only thing I can think of is the isolator switch, I used to switch it off every night after cruising, have I burnt it out?

[bizzard]

Ive got 4 leisure batts, 1x starter, 2 big blue sea isolator switches.

the starter has a built in coil but wont start off the key, it was fine one night, next day nothing, starter tested thats fine, batts fine the only way to start the boat is with a jump pack accross the 2 points on the starter motor, only thing I can think of is the isolator switch, I used to switch it off every night after cruising, have I burnt it out?

Jump across the two big in and out terminals on the engines isolator switch and see if it starts.

[p6rob]

Assuming the back of the isolator is accessible you could test that by putting a jump lead across the engine isolator switch poles.

Is there any signs of life on the dashboard with the ignition on, ie alternator warning light?

 

Rob

[TaffyRon]

Assuming the back of the isolator is accessible you could test that by putting a jump lead across the engine isolator switch poles.

Is there any signs of life on the dashboard with the ignition on, ie alternator warning light?

 

Rob

yes, the green light is on and switching the starter isolator on or off makes no difference and there is power at the starter, you cant bridge the starter but using it in combination with a jump pack starts it suggesting the battery is no good but had that tested and its fine. Need to pump the loo out, got a lean on

Jump across the two big in and out terminals on the engines isolator switch and see if it starts.

what instrument would be best to use?

Do isolator switches wear out? And can the starter still get a 12v feed from somewhere else?

[bizzard]

Mmm It might be best if you make sure all your battery terminals, the starters cable connections and the engines - neg cable back to the battery -neg terminal are all clean and tight before you go any further.

[kevinl]

I get through an isolator every couple of years even though I keep putting bigger ones in, it works enough to have the lights on but not crank the engine. Do you have a Vetus engine?

K

[Guest]

yes, the green light is on and switching the starter isolator on or off makes no difference and there is power at the starter, you cant bridge the starter but using it in combination with a jump pack starts it suggesting the battery is no good but had that tested and its fine. Need to pump the loo out, got a lean on

 

what instrument would be best to use?Do isolator switches wear out? And can the starter still get a 12v feed from somewhere else?

It has been mentioned on here previously that they are a common failure, though I don't know about that particular make as I understood they were a bit more 'upmarket' than the cheapos you often see fitted.

[TaffyRon]

When you turn the key you can hear the starter motor clicking in but it wont turn over

[Tony Brooks]

yes, the green light is on and switching the starter isolator on or off makes no difference and there is power at the starter, you cant bridge the starter but using it in combination with a jump pack starts it suggesting the battery is no good but had that tested and its fine. Need to pump the loo out, got a lean on

 

what instrument would be best to use?

 

As far as Bizzards test is concerned a large screwdriver would do as a first test but I would prefer to put both ring terminals on one stud. Take care not to short the spanner out.

 

You may find that you can effect a very temporary cure if its a plastic key type switch by screwing up ball of paper/cling film/tinfoil and putting that under the key.

 

As the green light does not go out it might also be the small cable between the ignition/starter switch and the solenoid (what I think you mean by a coil) not energising the starter. This could be a dirty/loose multi-way plug on the main wiring harness, cable fallen off either the switch or solenoid, faulty ignition/start switch, broken wire, loose terminals, or despite what you say about the starter testing OK (how and where was that done?) a faulty solenoid.

 

If its clicking and not machine gunning ignore the last paragraph.

Edited October 29, 2014 by Tony Brooks

[bizzard]

yes, the green light is on and switching the starter isolator on or off makes no difference and there is power at the starter, you cant bridge the starter but using it in combination with a jump pack starts it suggesting the battery is no good but had that tested and its fine. Need to pump the loo out, got a lean on

 

what instrument would be best to use?

Do isolator switches wear out? And can the starter still get a 12v feed from somewhere else?

You could isolate the isolator switch and by-pass it by putting both in and out cables onto the same terminal on the isolator switch.

[TaffyRon]

I get through an isolator every couple of years even though I keep putting bigger ones in, it works enough to have the lights on but not crank the engine. Do you have a Vetus engine?

K

thanks, that sounds exactly like it, I have a lister, just shelled out 45 quid on an identical isolator just hoping I havent wasted my money, cant fathom anything else

[p6rob]

yes, the green light is on and switching the starter isolator on or off makes no difference and there is power at the starter, you cant bridge the starter but using it in combination with a jump pack starts it suggesting the battery is no good but had that tested and its fine. Need to pump the loo out, got a lean on

 

what instrument would be best to use?

Not sure I can't get my head around that. If I've understood correctly, it sounds like it might be a -ve connection issue.

Have you got a jump lead available?

If so, rig the jump lead from the +ve battery connection to the positive post on the starter. If it now starts, check the positive circuit including isolator switch.

If nothing happens, attach the jump lead between the battery -ve and engine block. If it starts it's a fault on the -ve cable side.

If nothing happens, with -ve still jumped, try bridging the solenoid to +ve

[TaffyRon]

As far as Bizzards test is concerned a large screwdriver would do as a first test but I would prefer to put both ring terminals on one stud. Take care not to short the spanner out.

 

You may find that you can effect a very temporary cure if its a plastic key type switch by screwing up ball of paper/cling film/tinfoil and putting that under the key.

 

As the green light does not go out it might also be the small cable between the ignition/starter switch and the solenoid (what I think you mean by a coil) not energising the starter. This could be a dirty/loose multi-way plug on the main wiring harness, cable fallen off either the switch or solenoid, faulty ignition/start switch, broken wire, loose terminals, or despite what you say about the starter testing OK (how and where was that done?) a faulty solenoid.

it was done at a starter motor company, it works fine when not mounted on the engine too, plenty oil, flywheel turns by hand etc.

the starter engages it just wont turn without a jump pack and like I say all batteries are over 13volts

Local marina mechanic game out and hasnt got a clue, reccommends an electrician but surely its the copper contacts in the isolator no?

[TaffyRon]

And why would there still be power at the starter when isolators are switched off? Even when it srarted this was still the case, lister ha2 btw

[p6rob]

And why would there still be power at the starter when isolators are switched off? Even when it srarted this was still the case, lister ha2 btw

That would indicate an isolator switch fault. It's not fully breaking the circuit and presumably not making full contact either.

[TaffyRon]

That would indicate an isolator switch fault. It's not fully breaking the circuit and presumably not making full contact either.

thats my line of thinking, I will wait and replace the switch rather than take everything apart now and trying screwdrivers accross terminals and just replace it, will report back.

 

thanks for everyones input

[Alan de Enfield]

TaffyRon, on 29 Oct 2014 - 2:11 PM, said:

When you turn the key you can hear the starter motor clicking in but it wont turn over

 

Is it just 1 click, then nothing ?

 

Could be a total red-herring but on my small Tractor (Kubtota engine) I had problems starting it, eventually the starter motor did one-click but would not turn the engine over, tried again - 1-click but no turning over, tried again 1-click ..............

 

Took starter motor off, and tried again - the 'dog' was thrown forward (as if to engage with the flywheel) but there was no turning motion at all.

 

Took it into the alternator and starter motor repair man and £70.20 later it was back on and working 100%

 

This doesn't explain the light still showing when switched off, Try the master switch replacement first.

 

 

Edited October 29, 2014 by Alan de Enfield

[TaffyRon]

Is it just 1 click, then nothing ?

 

Could be a total red-herring but on my small Tractor (Kubtota engine) I had problems starting it, eventually the starter motor did one-click but would not turn the engine over, tried again - 1-click but no turning over, tried again 1-click ..............

 

Took starter motor off, and tried again - the 'dog' was thrown forward (as if to engage with the flywheel) but there was no turning motion at all.

 

Took it into the alternator and starter motor repair man and £70.20 later it was back on and working 100%

 

This doesn't explain the light still showing when switched off, Try the master switch replacement first.

 

they bench tested the starter as it was doing what yours did, the starter goes forward to engage with a click but wont turn without a jump pack, like a flat battery but its not flat

[bizzard]

Its possible that your starter button-key switch is not man enough to take the load of a hefty pre-engage starter motor like which an HA probably has. Usually a meaty relay needs to be added which can cope with this load. One of the old type car separate starter solenoids make an excellent relay, I have one on my ST2.

[TaffyRon]

As you say, switch off the isolators and all 12v lights go out in the boat except the alternator/ignition light

Its possible that your starter button-key switch is not man enough to take the load of a hefty pre-engage starter motor like which an HA probably has. Usually a meaty relay needs to be added which can cope with this load. One of the old type car separate starter solenoids make an excellent relay, I have one on my ST2.

Its coped ok for 20 years, why now?

[PaulG]

It's worth checking to see if you have a relay on the negative return from the starter motor circuit.

If this has failed open circuit you will still hear the click of the main starter relay but nothing will happen.

This was the cause of a failure to start on my engine a few years ago (Lister Petter LPWS3).

[bizzard]

As you say, switch off the isolators and all 12v lights go out in the boat except the alternator/ignition light

 

Its coped ok for 20 years, why now?

I suppose you could say that about a great many things that suddenly go wrong after giving years of service.

Is there a decent sized relay in the starter circuit between the start button or key start to the starter motor solenoid. I wouldn't be surprised if there is. Is your starter motor a pre-engage job with integral solenoid? Or you may have a big meaty diesel starter button or key switch which should cope with the load?

[TaffyRon]

I suppose you could say that about a great many things that suddenly go wrong after giving years of service.

Is there a decent sized relay in the starter circuit between the start button or key start to the starter motor solenoid. I wouldn't be surprised if there is. Is your starter motor a pre-engage job with integral solenoid? Or you may have a big meaty diesel starter button or key switch which should cope with the load?

yes its pre engage, yes its push button, the key switches on the ignition light then push big meaty button, but theres always power at the starter, solenoid is built in, cant find relay

[bizzard]

yes its pre engage, yes its push button, the key switches on the ignition light then push big meaty button, but theres always power at the starter, solenoid is built in, cant find relay

Connect a jump lead from the start battery's pos + post to the large IN terminal on the starters solenoid. Connect another jump cable from the engine mass or sometimes there is a - terminal provision for a Neg- cable on the starter motor body and to the battery neg- post. Then also fix a thin wire to the large pos IN terminal on the solenoid. If you touch the other end of that thin wire onto the small terminal on the solenoid ''the terminal that takes the wire from the starter button. solenoid, this will by-pass everything including the starter button circuit, and see if it works. If not your battery or big starter cable connections Pos+ and or Neg- might be suspect.

[TaffyRon]

Connect a jump lead from the start battery's pos + post to the large IN terminal on the starters solenoid. Connect another jump cable from the engine mass or sometimes there is a - terminal provision for a Neg- cable on the starter motor body and to the battery neg- post. Then also fix a thin wire to the large pos IN terminal on the solenoid. If you touch the other end of that thin wire onto the small terminal on the solenoid ''the terminal that takes the wire from the starter button. solenoid, this will by-pass everything including the starter button circuit, and see if it works. If not your battery or big starter cable connections Pos+ and or Neg- might be suspect.

done that, it only starts doing that with jump pack