How do I test for Spark?

mreinsmith

Petty Officer 3rd Class
Joined
Jun 15, 2008
Messages
82
How do I perform a spark test?

Is there a tool I need?

Can I get one from Sears or an Autoparts store?

How do I make sure it's properly grounded and/or "gapped"?

I see people on the board talking about testing for spark and the clymer manual describes it as well. But I'm still not clear on the tools and proceedure?

any help is appreciated

Thanks
 

Leinenkugel#1

Seaman
Joined
May 27, 2008
Messages
61
Re: How do I test for Spark?

You can do the old screw driver test, ground screw driver to block, while holding it against the spark plug end, try it in dusk (low light) and you will be able to see the arc. If good spark, you should clearly see a good solid arc.

(need 2 people) Watch out for a little jolt, make sure your screw driver has a good rubber handle. :eek:
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: How do I test for Spark?

Search iboats for Joe Reeves posting directions to build your own spark tester, cheap and easy, (like me), and works very well.
 

Leinenkugel#1

Seaman
Joined
May 27, 2008
Messages
61
Re: How do I test for Spark?

Or go by a tester any auto parts store for about 10 to 15 bucks

Or

Spark Tester - Home Made
(J. Reeves)

A spark tester can be made with a piece of 1x4 or 1x6, drive a couple nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail.
 

rodsailor

Cadet
Joined
Jul 25, 2008
Messages
28
Re: How do I test for Spark?

You can buy a spark tester at Autozone or any of the other chains for less than $6 (NAPA might be a bit better, but more expensive). The one I bought from Autozone has an alligtor clip on one end, a spark wire terminal on the other, and an adjustable screw that allows you to approximate the voltage from the coil. The housing is black, and I can see the spark clearly from the helm on a bright day. I clip the alligator to the stainless plug on the top of the waterjacket above the thermostat, so the tester is visible over the flywheel or from the side. Works very well.

Rodsailor
 

mreinsmith

Petty Officer 3rd Class
Joined
Jun 15, 2008
Messages
82
Re: How do I test for Spark?

you guys are the Best. Looks like I have good spark (got a tester from NAPA)

Now should I build the gap tester and check that next? Or is it good enough to see that we are actually getting spark.

BTW - the problem is that we've got the idle set nicely, but as soon as we "snap" the throttle it dies.

Thanks again
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: How do I test for Spark?

See my private message to you. We can get together and I will set up your engine. Your bayliner did come with a functioning tach, didn't it?
 
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