Problem Testing For Spark

Sureshot

Sureshot

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Experts, please tell me where I'm messing this up. Trying to test for spark on a 50 HP 2-stroke Johnson:
1) Remote starter switch hooked up to crank the motor instead of using keyswitch
2) Spark plug gap tester (from Autozone set to 7/16") hooked up to plug #1 and grounded to headbolt
3) Keyswitch in the on position

Motor cranks over easily but don't detect and spark on gap tester. Is this the correct procedure to verify spark? Anything I'm missing or forgetting?
 
W

Will Bark

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Re: Problem Testing For Spark

My spark tester from AutoZone you put the plug wire on the tester and ground the other end to the block and spin the engine; no sparkplug is involved at all. Maybve i'm misreading what you mean and in that case if you are not getting anyspark you have a problem. Is the battery charged up enough to spin the engine 250-300 revolutions per minute?
 
BonairII

BonairII

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2,727
Re: Problem Testing For Spark

If you don't detect spark....maybe it's because that cylinder isn't firing at all.

Change the ground location to verify that you have a good ground.
 
metriccrescentwrench

metriccrescentwrench

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Re: Problem Testing For Spark

Does your engine have an emergency kill switch? If so that could be the culprit. Try the tester on the other cylinder(s), see if there's spark there. Shorten the gap to see if you detect a spark (yes, it's supposed to be able to jump 7/16", but if it'll jump something less then at least you know what's going on).
 
Sureshot

Sureshot

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Re: Problem Testing For Spark

Battery is new. Reads 12 V with a multimeter. Didn't charge it when I bought it though, not sure if that's necessary. I have the spark plugs in the holes but I am not connecting the wires or tester to them. I've tried a couple of bolts on the head and still don't get anything. Regarding the killswitch, I don't have one hooked up. I have a lanyard that hooks onto the keyswitch and when pulled, forces the key to off. Thanks guys.
 
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hotshot123

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Re: Problem Testing For Spark

just a reminder, if you are using a remote starter button, you still need to have the key on before you will get spark. (unless you have the kill wire disconnected)
 
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boobie

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Re: Problem Testing For Spark

Take the spark plugs out once what happens.
 
Sureshot

Sureshot

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Re: Problem Testing For Spark

Took out plugs and still no spark when cranking. Key switch is in the on position.
 
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boobie

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Re: Problem Testing For Spark

As Metric said, did you try the spark tester on both cyls ??
 
Sureshot

Sureshot

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Re: Problem Testing For Spark

Yeah both plug wires. Was thinking maybe a bad tester but I checked and it works on my lawn mower.
 
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AlTn

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Re: Problem Testing For Spark

have a model no. or know the year?
 
Sureshot

Sureshot

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Re: Problem Testing For Spark

AITn its a 2000 model# is j50plssm
 
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boobie

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Re: Problem Testing For Spark

Find the black/yellow wire going to the power pack and disconnect. Then recheck.
 
Sureshot

Sureshot

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Re: Problem Testing For Spark

Fuse is good. I tried cranking it with the black/yellow wire disconnected from the PP but still no spark. I've screwed up something I'm afraid. Had it running a few weeks ago with no problem but did have an issue when I tried to turn the motor off via the keyswitch. The engine kept running so I had to flood it out. I replaced the keyswitch because it was pretty worn and tested again yesterday. I had a trouble starting initially (no spark). My manual instructed me to check the stop circuit by disconnecting the black/yellow wire at the PP like Boobie suggested. At the same time I had switched over to an inline spark tester that was connected to the top cylinder and the motor fired right up. I reconnected the black/yellow wire to the power pack and for the rest of the afternoon the motor fired up easily but I still couldn't kill it with the key and had to flood it out. Could it be something going on w/ my power pack?
 
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boobie

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Re: Problem Testing For Spark

When you put the black/yellow wire back in did it make good contact with the pack ? If it didn't and the mtr is still running you could have a wireing harness prob. The reason I say this is you couldn't shut the mtr off after you reconnected it.
 
metriccrescentwrench

metriccrescentwrench

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Re: Problem Testing For Spark

Wait a minute. Sometimes it runs but won't turn off with the switch. Other times you can't get a spark when trying to start with a remote starter and the keyswitch in the run position. I'd lay money that the keyswitch is wired wrong. One thing to check (cause it bit me in the *** when I rebuilt my Checkmate) is to verify that the new keyswitch has all the terminals in the same location with the same labels as the original. In my case the replacement switch (aftermarket, not OEM) had one of the terminals labeled differently.
 
Sureshot

Sureshot

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Re: Problem Testing For Spark

I disconnected the black/yellow wire right before an amphenol connection heading to the power pack. Does this make a difference? Should I have disconnected the black/yellow wire at another place on the powerpack? I checked the black/yellow wire (heading back to the harness and keyswitch) with an ohmmeter and it appears to measure correctly in both the off and on positions so I'm thinking my keyswitch is ok.
 
Sureshot

Sureshot

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Messages
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Re: Problem Testing For Spark

Issue was a bad rectifier. The CDI electronics troubleshooting guide has that as the next step after disconnecting the black/yellow wire from the PP. After I disconnected the rectifier I was getting spark on both plug wires. Thanks everybody for the help.
 
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