Engine Fire/burnt out starter motor

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aidancoughlan

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further to previous post on my unfortunate first day out ..... (see
http://www.ybw.com/forums/showflat.php/Cat/0/Number/768474/an/0/page/4#768474), I've removed the starter motor for checking/refurbishment, and taken some photos. Just thought I'd post them here in case anyone might spot any clues from the photos. Was this a wiring issue, or a problem in the starter motor/solenoid?

P7020173.jpg


While I'm no expert, I couldnt see much problem in the wiring other than the wire connected down near the filter was not well connected - the screw on the terminal was very loose, and in the phot using the mirror, the blue wire going to the engine panel was very close to the positive output from the alternator, and the battery cable - although I couldnt actually see if there was any contact made here.

Does anyone know engine wiring well enough to hypothesise if either of these could cause the starter motor/solenoid to burn?

I looked at the wiring at the other end at the engine panel, and nothing seems to be amiss other than some green/corroded terminals.


more photos at burnt out starter photos
 
If it was a wiring fault I'd expect the wiring to be damaged along its whole length, looking at photos it seems that the wiring was only really burnt close to the solenoid / starter. Also looking at the starter it seems to have got extremely hot as the paint was blistered.
 
I had a burnt out starter on my MG - looked very similar, all the cables burnt and the starter needed rebuilding - just traded in for a new smaller one!
 
Aidan,
From the pictures I would say, that the fire started in the starter. Flames go up so that's why the solenoid is also fried.
I would also say, that the starter has been spinning all the time (starters are not made for this) either with the bendix in the flywheel gear or just spinning on its own. The solenoid does 2 things: 1 it pushes the bendix to the flywheel and 2 if the bendix is in this position, the contact is made to spin the starter.
If the mechanical engagement system is ok, the starter can only spin if the bendix is on the flywheel gear. If the mechanism is not ok, then it is possible for the starter to spin freely. I am wondering why you did not have starting problems though...
 
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If it was a wiring fault I'd expect the wiring to be damaged along its whole length, looking at photos it seems that the wiring was only really burnt close to the solenoid / starter. Also looking at the starter it seems to have got extremely hot as the paint was blistered.

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The starer did get really got - when doused with water (I know, I know...) it sizzled like a frying pan.


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just traded in for a new smaller one!

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- it's on its way to the local repair shop, but I'm expecting to need a new one.


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I would also say, that the starter has been spinning all the time (starters are not made for this) either with the bendix in the flywheel gear or just spinning on its own.

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The bendix (the cogs that meet with the flywheel?) was not engaged with the flywheel, at least after the engine was stopped - I dont know if it was engaged throughout the time the engine was running though.


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If the mechanical engagement system is ok, the starter can only spin if the bendix is on the flywheel gear.If the mechanism is not ok, then it is possible for the starter to spin freely. I am wondering why you did not have starting problems though...

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Didnt have any starting problems, although the start battery did take a hammering (down to 8.2 volts !). I wonder if its possible that the engine switch may have stayed in the start position, leaving the starter motor spinning all the time, or if an internal fault caused it to continue to run. (From the state of it, it does look like the starter continued to run). In either case, shutting the engine down caused it to stop.

Hopefully the repair shop will diagnose the fault - I dont want to replace with a new starter and have the same problem. I've already refurbished the alternator since it wasnt charging, and it now looks like the starter may have been the fault (alternater output goes nowhere), and the alternator may be fu*%ed again !

thanks for the input guys...
 
My thoughts on this:

Not the wiring cause it is only damaged in the area of the worse damage from the starter

Probably the solenoid. I suspect that it jammed on on start thus the starter was continuing to wizz round draining the battery. This caused it to get "hot" and the heat allowed the solenoid to disengage.
 
I had a similar problem this week. My starter motor was refurbed/reconditioned about 2 years ago and it seems they did a hash of it. My new engineer has taken it out again and rebuilt it again but he says it is knackered and realy needs replacing. A new starter motor is around €700 - which was his initial quoate so as usual that price will probably rise. This seems a lot to me. Does anyone have any views? My engine is a Volvo 2003.

regards

David
 
I have two guesses:

Either your starter motor is short circuit internally, causing the thing to become VERY hot and subsequentially overloaded the solenoid, this becoming very hot as well. This might also have impacted your battery.

The other cause migh be that the bendix did not retract after starting, this causes your engine to 'pull' the starter at much to high revs, effectively frying the whole thing.

Arno
 
No way should a starter motor be £700 unless its for something totally rare like a 36 volt starter for a moon buggy.

A brand ne starter when I bought one for my Yanmar was about £150 from memory.

I would recommend that you take it along to an auto electrical repair shop - most big towns have one. See what a non yotty place says.
 
As someone has already said, heat / flames go upwards so to my mind its the motor itself which is suspect. This has heated enough to bubble the paint but has not heated up enough to burn the paint on what looks like the heat exchanger above the solenoid. Whats more, the overheated wires are only in the region of the starter itself so its not like the dead short I once saw on a Sadler Starlight that m,elted the insulation all the way back to the battery.

I reckon it is more likely to be the bearings at that end of the starter motor with the burning paint scorching the solenoid. Dont think its electrical in the external wiring.

Anyway, can you post the result so we can see who's guesswork (if anyone's ) is correct?
 
From the visual and verbal evidence

I'd suggest your solenoid stayed closed after the engine had started, the most overheated item is the connection from solenoid to starter motor.

Further evidence is the fact that your starter battery was flattened (incidentally that will probably also be NU).

Certainly, with the starter being turned by the engine for any time that would have overheated it as well.

I suspect the Bukh is a good old-fashioned worm-engagement starter, unlike most modern pre-engaged starters - this makes the chances of sourcing one from anywhere else remote (and knowing Bukh spares prices I shudder to think what the cost will be).

If you can still read the plate on the starter send me the typ/no by PM - the maker is probably Bosch - and I'll try and get some matches for you.

Incidentally a jammed-on solenoid is very rare - I'v only had it happen once and was lucky enough to hear it had happened and able to disconnect the battery.
 
Have a look at www.lsm-diesel.dk

Also try your local Partco or Lucas for an exchange starter although I am not sure they will acccept a burnt out one in exchange.

Plan "b" is to find out what else uses the same starter (Partco or Lucas should have an applications listing for the starter motor) and visit your local scrap yard!
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“Artificial intelligence is no match for natural stupidity”
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Re: From the visual and verbal evidence

Hi Charles,

I have a Bukh too, so would appreciate your posting details/ref. numbers any equivalents you can come up with for Aidan. Would be very useful to have that info ....... just in case!!

Cheers Jerry
 
just to add my thought

is or has ther been a short onto the blue wire, or did the starter switch stick in the start position, for if the blue wire was fed a supply, the starter motor would spin untill it burnt out.
 
I had this problem on an Essex V6 the bendix gear stuck on the flywheel whilst starting and nicely toasted everything (sod's law dictating it was in the middle of no where in South Africa's Eastern Transvaal )

regards Joe
 
You were lucky - two wekends ago in Cowes/Whippingham a motor launch was completely burnt out when an alternator caught fire, setting the whole boat ablaze - a total loss
 
Hi all, many thanks for all the input. Lots to investigate, and much appreciated. I'll post with any updated information since it seems to have aroused curiosity.


I've sent off to lsm-diesel, and some UK Bukh dealers for info/price on a replacement starter & to see if an alternative will fit.
Price from Bukh UK is £330+vat.
Charles, you are right it is a Bosch starter - the model number is written on the case as Bosh 0 001 314 031. I've searched the web for references to no avail.

I took the starter Motor to a back-stret alternator/starter shop today - alternator is fine, but the starter is literally burnt to a cinder inside - definitely unrepairable.

The alternator + output ring terminal was connected at an angle that put it extremely close to the Blue wire (solenoid exciter), and apparently (according to BUKH UK) a short here would have caused exactly this problem. However, it's probably unlikely that I can deduce definitively that this was what happened. - I'll probably replace the starter and wiring and watch it closely to ensure there isnt a remaining problem with the ignition.


best regards,and thanks,
Aidan.
 
A few points to make:
The pic appears to be of a pre-engage type starter, not an inertia type as suggested in one post. This type was, I believe, prefered for diesel engines long before they became universal on small petrol engines. Sticking in engagement with the starter ring should not cause the motor to be turned at high speed by the engine as they incorporate a uni-directional cluch to prevent that. Anyway if that did occur I suspect the noise would be more that a whine (IMHO)

Welding shut of the solenoid contacts is a (remote) posibility but they would not have opened again when the engine was stopped, the motor would have continued to turn (and whine). Similarly if part of the solenoid mechanism had jammed.

A short in the wiring between the alternator output, which wil be directly connected to the battery, and the solenoid could have occured at any time, would probably have been much more intermittent than the fault appears to have been and would not have cleared when the engine was stopped.

All this leaves the posibility of a wiring fault or, in my opinion the most likely, a faulty "ignition" switch not returning back properly from the start position.

I am assuming the engine is stopped by turning off the "ignition" switch as each time the engine was stopped the whining noise stopped and the only Bukh installation I have sailed with worked like that (in a Fulmar).

Any problems relating to the starter motor itself will be overcome by the fitting of a new one. You will obviously take care that no short can occur between the alternator and the solenoid and I strongly advise that you check the "ignition" switch very VERY thoroughly for the possibility that the fault lies there, or perhaps in the wiring before you try out the new motor. You won't want to burn out another or risk even more serious consequences.

If I am wrong about the way you stop the engine the I am probably wrong about the cause, but I don't think so.
 
Hi vic,
You are correct about the Bukh ignition engine shutoff mechanism - key based rather than a pull-stop handle.
Your post above sounds like a very good argument for a closer look at the starting switch.

Incidentally, when I ran the engine for 40 mins before the second outing the engine wouldnt shut off by using the key. It turned out the start battery had been (incorrectly) shut off after starting (alternator should still output through the VSR?) , and the ignition couldnt stop the engine. When the start battery switch was turned on again it worked ok. I dont know if this throws any more light on the matter.

I will try to get out to the boat this again week (if work permits!) to take off the engine panel/ignition to check it.

I am starting to think of biting the bullet and getting not just a new Starter Motor, but also a pre-wired loom and new engine panel from Bukh, as the original panel is 20yrs old and the components are all green with corrosion - replacing the individual bits adds up to the cost of a new panel.

best regards,
Aidan.
 
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