Engine/Ignition problem

[alan_fincher]

Some of the way this thread has gone is yet another classic example of the kind of misunderstandings that can occur when everything is done at the keyboard, with no personal contact, vocal tones, or body language.

 

I can't imagine that John and Bones would be having a face to face conversation like this, would they ?

 

But like some others before me, lets try and move things forwards…..

 

My thoughts…...

 

If a genuinely almost new starter battery is being used, and it was fully charged before you attempted to start, but discharged within only a few minutes, then I agree with Allan that some kind of internal electrical short in the starter sounds the most likely. You would have to take it somewhere to look at - you'll definitely not be able to sort that yourself..

 

But on the info as posted, I'm not yet fully convinced that this is the case - i.e. a good battery going from fully charged to unusable in only minutes. Whilst possible, it's not that usual, and I'd expect your cabling to be getting significantly hot, (not just warm), due to the massive currents involved.

 

So it's important to understand exactly how are you measuring "charged" or "discharged", or ("OK", or "not OK"). Just putting a voltmeter across the terminals, and measuring voltage with no load on will not tell you very much. Yes, if it reads well under 12 volts, its clearly not going to work. But a reading above 12 volts is easily possible with a battery not capable of starting anything.

 

John is absolutely correct that you must try and measure the volts when the battery is under load, i.e. trying to crank the engine. If the volts drop badly as you try and start, then it's not a well charged battery.

 

So how exactly are you recharging the battery before your next attempt. If you were just using a car charger with relatively low output, it could take into days rather than hours to get from flat to fully charged, (but, at risk of repeating myself, would still be capable of registering well over 12 volts "off load" after a few hours).

 

Example, if you battery is 100 Amp Hours, and your charger only averaging 4 amps, then even if the process was 100% efficient, you'd need 25 hours of charging. In practice at least a day and a half might be required, as you always have to put more in than it is quoted as being able to give out.

 

But on the other hand……..

 

If you are now totally confident of your battery, and it WAS NOT in fact flattened by a few minutes of trying, then the short circuit theory becomes far less likely, and the "poor connection somewhere" thing comes far more into the list of possibles. The people who have said the smoke may be coming from a badly made arcing connection could then be right……

 

So, before I speculate further…..

 

Please walk us again through exactly how you are determining your batteries state of charge, how long you are charging it for, and at what average current, and how long you are now able to try and start the engine for before the battery is significantly flattened…..

 

Or if none of that makes enough sense, please ask questions, and I'll see if I can find another way of putting it…..

 

Alan

[Bones]

I am not re-starting this thread at all.

 

However, I have just heard from the starter motor genius and the starter motor was completely horrific and needs a total overhaul. Initial prediction was that it was full of diesel and oil (it is very low slung, and there is evidence of someone trying to prevent that happening with all the sealant), but that is not the case. It appears to be funked. He is going to re-do it for 85pounds which I am pleased about. He has an excellent reputation which is super smashing dandio.

 

 

BONES DUCKS, GRABS COAT AND RUNS to the virtual bar..... offers to buy all a drink.

Edited March 23, 2006 by Bones

[Keeping Up]

If it turns out I'm wrong and that taking it off was a waste of time (not nearly as much as the time wasted putting it back on, of course) then I'll humbly grovel in your bilges and buy you a bottle of something drinkable when I see you.

I am so glad to hear that I will not be spending my time grovelling in your bilges.

 

Cheers

 

Allan

[Bones]

I am so glad to hear that I will not be spending my time grovelling in your bilges.

 

Cheers

 

Allan

 

 

well... when you put it like that! Actually it was horrid. But as we all say - now I know how it won't be so difficult next time. I am writing a comprehensive manual for this boat just incase anyone buys it in the future. History is important!

[Alec Gatherer]

Actually Bones, history is bunk.

But only in a 12-berth hire boat.

[Maffi]

Given that there is a lot of talk on the forum about starters, I have taken the liberty of drawing the internal workings and putting them in the gallery. I have not included the main starter contacts.....I am still working on that, but will post that drawing as soon as I have finished it.

 

PRE-ENGAGE STARTER MOTOR

 

 

Edit:Done now this should help

STARTER SOLENOID

 

Edit: And now this

BENDIX STARTER

I haven't seen one of these for sometime, but I think it's right.

Edited March 24, 2006 by Maffi

[Alastair]

How damn obliging and helpful of you!

 

Once I've finished the BSS work, I have a dicky starter on a lister to look at. I shall certainly study your drawings before I start, should save me lots of head scratching, ta.

[Maffi]

How damn obliging and helpful of you!

 

Once I've finished the BSS work, I have a dicky starter on a lister to look at. I shall certainly study your drawings before I start, should save me lots of head scratching, ta.

 

 

I hope it helps, but if you have a Bendix starter it's different. The solenoid is separate from the Motor. And the pinion is of the slip/throw type, but that's another drawing, Ho hum.

Edited March 24, 2006 by Maffi

[Alec Gatherer]

I hope it helps, but if you have a Bendix starter it's different. The solenoid is separate from the Motor. And the pinion is of the slip/throw type, but that's another drawing, Ho hum.

Is that not a matter of a pinion?