Spark Gap Tester...KCLOST???

[studlymandingo]

I just bought a spark gap tester, I'm not sure if I need one; but after reading several posts by KCLOST, I decided it would be prudent to have one in my arsenal. I like tools anyway! <br /><br />I have a Mariner 150 and the idle is a little rough, doesn't seem to be a miss though and never stalls. So I decided to check the spark gap. My question is, do I perform the check on a running motor, or while the system is disabled so it will only turn over and not start?

 

[bootle]

Re: Spark Gap Tester...KCLOST???

I have this model tester and it works fine, it takes the hassle off of having to ground all of the plugs. http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_391735_391735

 

[saumon]

Re: Spark Gap Tester...KCLOST???

Originally posted by Darth D Invader:<br /> I have this model tester and it works fine, it takes the hassle off of having to ground all of the plugs. http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_391735_391735

I always think that the kill switch disable the ignition system, so no spark is produced...

 

[dajohnson53]

Re: Spark Gap Tester...KCLOST???

Originally posted by Darth D Invader:<br /> I have this model tester and it works fine, it takes the hassle off of having to ground all of the plugs. http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_391735_391735

Hi: does this tester actually test the strength of the spark? I have this tool which you can adjust to check the strength:<br /><br /> spark plug tester with adjustable gap <br /><br />A while ago there was someone who posted a neat home-made version that would test spark strength for all cylinders at once. A search could probably find it.

 

[bootle]

Re: Spark Gap Tester...KCLOST???

Originally posted by saumon:<br />

Originally posted by Darth D Invader:<br /> I have this model tester and it works fine, it takes the hassle off of having to ground all of the plugs. http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_391735_391735

I always think that the kill switch disable the ignition system, so no spark is produced...

You are correct, i edited out my mistake prior to your post, i had a temporary brain freeze, i usually disable the killswitch when doing a compression test, sorry for the confusion.

 

[bootle]

Re: Spark Gap Tester...KCLOST???

"Hi: does this tester actually test the strength of the spark? I have this tool which you can adjust to check the strength:"<br /><br />D,<br />It does not test the actual strength, but one can see the intensity of the spark, as they move on to test the other plugs, one can then visually verify which plug has the weaker spark.

 

[dajohnson53]

Re: Spark Gap Tester...KCLOST???

Thanks.

 

[studlymandingo]

Re: Spark Gap Tester...KCLOST???

<br /><br />This is the tester that I used. I have a couple of cylinders that have a weaker spark than others. I am first going to replace the plug wires. I talked with Mike Black (Myoutboards) who suggested the "make your own wire" kits from high energy ignition or the likes. I'll see where that gets me and keep you posted.

 

[studlymandingo]

Re: Spark Gap Tester...KCLOST???

Btw: Does anyone know where I should be setting the gap on this thing?

 

[saumon]

Re: Spark Gap Tester...KCLOST???

unscrew till 3/8

 

[studlymandingo]

Re: Spark Gap Tester...KCLOST???

Just put some new 8mm spark plug wires on. I don't seem to have any misfire, but there may be a couple of cylinders that have a slightly weaker spark than the others. While I was replacing the wires, I pulled the plugs and shot some Deep Creep into each cylinder. Got a good bit of crap out of the exhaust when I fired it up.

 

[KCLOST]

Re: Spark Gap Tester...KCLOST???

Studlymandingo,<br /><br />Use the gap tester on one cylinder at a time, with the engine running (on the muffs or in the water)... Test at idle.<br />The spark should jump a gap of 7/16"... And check the spark repetitiveness.. Are all consistent?

 

[studlymandingo]

Re: Spark Gap Tester...KCLOST???

The spark is jumping the gap on all cylinders, I cannot really tell if it is consistent though.

 

[KCLOST]

Re: Spark Gap Tester...KCLOST???

Well that is good....<br /><br />Have you checked compression on all cylinders?<br /><br />You should be able to see any inconsistent spark however... IF there is any miss you should be able to tell that there is a problem on the cylinder.... It just takes a little observation on each..

 

[studlymandingo]

Re: Spark Gap Tester...KCLOST???

Yes my compression is good on all cylinders and withing a couple of lbs of one another. The motor seems to run well above 1500 or so RPMs the idle is just not a purr. I will try the spark gap test again tomorrow evening when the sun is almost gone, it's so bright here in the daytime that it's hard to be sure on the spark. My #6 plug looks wetter (with fuel) than the rest which is what gives me suspicion that there may be a spark issue. I haven't ruled out the carbs yet either.

 

[KCLOST]

Re: Spark Gap Tester...KCLOST???

Is this a new problem, or has the motor always been like this???

 

[studlymandingo]

Re: Spark Gap Tester...KCLOST???

I just got this boat a couple of months ago. Since I have had it the idle has been just a bit rough. It never wants to die, and fires right up when the key is turned. Prior to this rig, I have had several I/Os and a couple of 3 cyl. 'rudes which amount in my opinion are as simple as a lawnmower engine. This is a bit different, and I am learning this setup as I go. I feel like I should be getting a little more out of this motor.

 

[studlymandingo]

Re: Spark Gap Tester...KCLOST???

any ideas as to what this wire is? It has a rubber plug in the end that looks like it may be factory. Is there a possibility this could have anything to do with the idle?<br />

 

[KCLOST]

Re: Spark Gap Tester...KCLOST???

I think that is the mercury switch... <br /><br />Someone elso may be able to confirm that...

 

[studlymandingo]

Re: Spark Gap Tester...KCLOST???

Mercury Switch? What would that be for? It is a red wire with a white stripe, it has a female butt connector on it (brass connector with a clear sleeve over it); inside the butt connector is a rubber plug.