austmoke

Author Topic: Coil (?) mystery  (Read 150 times)

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Saso

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Coil (?) mystery
« on: January 04, 2021, 11:26:14 AM »
Driving back from beach on New Year's Day with 10-year-old daughter, Moke just stopped. Would turnover (crank) but would not fire. Tested for spark at the HT lead and at the plugs and all seemed fine. Test fuel flow to carb and that seemed fine, too. Replaced coil next day and Moke started and *seems* to be running fine.

However, I've tested the old coil with mulitmeter and it seems ok (3.1 ohms and 12100 ohms) so am concerned there is something else going on. Any thoughts?

A couple of observations:

It has been running beautifully.
It was raining when it stopped (of course), though not especially heavily.
About a kilometre beforehand, when I throttled up after a downhill coast, it backfired once.
It then started to kick (very, very slightly) when powering up to 80 kmh, uphill.
On the following downhill run, it stalled -- coasted to a stop and simply wouldn't restart.
On investigating I found the housing/cover for the starter was loose -- like really, rattly loose. Tightened it up but still wouldn't start (thought it might have been an earthing issue).
Also noticed a very small spark from the +ive terminal (or rather, the wire attached to the +ive terminal) of the coil to its 'nose'.

Thanks.

Steam

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Re: Coil (?) mystery
« Reply #1 on: January 05, 2021, 10:43:44 AM »
I would suspect the last line of your post gives the answer.
If the coil tests ok and gives a good blue white spark rather than an orange colour then the loose connection was probably the cause which you have remedied by disconnecting then reconnecting.
You should investigate exactly where and why the small spark was present as it will in all probability fail again and let you down at the least desirable time ( as defined in Murphy's Law).
Cheers, Dave

Steam

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Re: Coil (?) mystery
« Reply #2 on: January 05, 2021, 10:48:34 AM »
Actually, just reread your last line and figured by nose you may mean the HT connection which suggests a crack in the bakelite or a carbon track to the terminals. The new coil will have fixed that if this is the case.
Cheers, Dave

Halfpint

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Re: Coil (?) mystery
« Reply #3 on: January 05, 2021, 10:02:29 PM »
Hey there Saso, long time ;)
I was also thinking with rain and humidity some condensation in the dizzy cap or leads. A dry rag and some WD40 in the tool kit may help.
HP
The happiest of people don't always have the best of everything, they just make the best of everything they have.

Tim

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Re: Coil (?) mystery
« Reply #4 on: January 06, 2021, 12:00:07 PM »
Moisture mixed with dirt or other contaminants on the nose of the coil or the ignition leads will do it too. Wipe them all off with something like WD40 and a rag.

Tim
1951 Morris Commercial J Type Van
1955 BSA C11G
1961 Morris Mini Traveller
1969 Triumph TR6R
1977 Leyland Moke Californian

Driving a Moke with a hardtop is like having a shower in a raincoat.

matpaul

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Re: Coil (?) mystery
« Reply #5 on: January 06, 2021, 01:09:40 PM »
Had a similar problem on mine. In the end I believe it was bad connection/s to the primary side of the coil. Which also would be inadvertently/ temporarily ‘fixed’ when i played with the connections or changed the coil.
Cheers,
Mathew.

Saso

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Re: Coil (?) mystery
« Reply #6 on: January 06, 2021, 01:54:25 PM »
Thanks all. Some reassuring advice and info there. I am sure you can imagine my 10-year-old's face when broken down, in the rain, on New Years Day, and am deploying Damage Control Plan A such that she doesn't become permanently wary of such potential mishaps in future.