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Old 08-09-2018, 08:38 PM   #1
Cape Codder
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Default Checking Spark

I have seen several times on this Forum to pull the coil wire out to check for a Spark. They usually go on to say you should have a nice blue spark approx. 1/2" long. So my question is if I don't have a strong spark should the Coill be changed or........?

Thanks for any advice or help!
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Old 08-09-2018, 09:48 PM   #2
1955cj5
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Default Re: Checking Spark

I had also read about checking the coil...

I finally got around to checking it and my old coil had a weak yellow spark barely 1/4" long..

I replaced the coil and re-tested and I had a hot blue 1/2" or greater spark...big difference.

I think it runs much better now.

I only changed the coil, everything else remained the same.

The old coil is now my spare....
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Old 08-09-2018, 10:48 PM   #3
BILL WILLIAMSON
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Default Re: Checking Spark

You need to study the BASIC, SIMPLE ignition system to UNDERSTAND HOW it works, then you can do basic, simple tests.
Bill W.
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Old 08-09-2018, 11:59 PM   #4
Chuck Sea/Tac
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Default Re: Checking Spark

Quote:
Originally Posted by 1955cj5 View Post
I had also read about checking the coil...

I finally got around to checking it and my old coil had a weak yellow spark barely 1/4" long..






The old coil is now my spare....

Toss it and buy a new good one, they are cheap. Your old one is failing and may not even get you a few miles down the road.
A bad condenser can have the same symptoms.
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Old 08-10-2018, 05:08 AM   #5
old31
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Default Re: Checking Spark

x2 with chuck

A few weeks a go I had the same symptoms, changed the condenser and it was fixed.
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Old 08-10-2018, 05:40 AM   #6
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Default Re: Checking Spark

Quote:
Originally Posted by BILL WILLIAMSON View Post
You need to study the BASIC, SIMPLE ignition system to UNDERSTAND HOW it works, then you can do basic, simple tests.
Bill W.
Good reply, a google search can be your friend. Everyone should take a few minutes to try and understand the basic theory of how a combustion engine operates and runs. The internet is a fantastic tool if used properly, but it has also made some very lazy.
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Old 08-10-2018, 09:15 AM   #7
BILL WILLIAMSON
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Default Re: Checking Spark

One of our Guys has a GREAT website for learning. I "think" it's MODELABASICS.COM
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Old 08-10-2018, 09:24 AM   #8
katy
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Default Re: Checking Spark

Quote:
Originally Posted by BILL WILLIAMSON View Post
You need to study the BASIC, SIMPLE ignition system to UNDERSTAND HOW it works, then you can do basic, simple tests.
Bill W.
Ditto
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