2001 johnson 150 weak spark!!

wilson750

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My 2001 (thought it was 2002 in other posts) Johnson 150 seems to have weak spark. Its getting a good amount of gas and just wont fire back up. I can hold any of the spark plugs to ground with my hand and feel a very weak shock. You would think a spark from a outboard would hurt or throw your arm. So I am guessing it either has a bad powerpack or stator? I do not have a tester for 7/16ths gap to see if it will jump. The spark is also a very light blue. I thought it should be a dark blue? I replaced the plugs and it did not change!! ANy help?
 

daselbee

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Re: 2001 johnson 150 weak spark!!

Since you don't have the proper spark tester, and since you are willing to hold the plug to ground to test spark, try this test instead. Remove the plug itself from the plug wire, hold the plug wire itself close to ground, and then crank the engine. Let us know what the results of the test were.
 

boobie

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Re: 2001 johnson 150 weak spark!!

Guessing costs $$$$$. You need a manual and test equipment to work on this yourself.
 

wilson750

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Re: 2001 johnson 150 weak spark!!

Well its got to be one if the 2. Atleast I hope. I'm gonna grab a spark tester and a manual. A manual doesn't always help I have learned.
 

boobie

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Re: 2001 johnson 150 weak spark!!

If you get the OEM Factory Service Manual it will. And if you have one it will save you some $$$$$ in the long run.
 

wilson750

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Re: 2001 johnson 150 weak spark!!

If you get the OEM Factory Service Manual it will. And if you have one it will save you some $$$$$ in the long run.

Thanks, I will report back with my findings.
 

wilson750

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Re: 2001 johnson 150 weak spark!!

Went to the boat over the weekend, installed th powerpack and stator and still no change in spark.Still very week. Did a compression test on all 6 and came up with 95-100 which is all good. This is driving me nuts!!! Now im thinking its a ground wire? maybe a bad key switch? Who knows. I saw that you can unplug the harness in the motor and jump the boat that way? If anyone can suggest some things for me to try please help me out.. Im ready to call a mechanic to come out to the boat in the slip.
 

daselbee

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Re: 2001 johnson 150 weak spark!!

Where did you post the results of the proper spark test? You know, using a tester that checks for the ability of the spark to jump 7/16"...Did I miss it?
 

wilson750

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Re: 2001 johnson 150 weak spark!!

I dont have a tester for 7/16ths. I did have a tester that you hook up and it lights up a bulb. The bulb would hardly even glow. If the spark plugs didnt jump 7/16ths what would you suggest I do next?
 

daselbee

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Re: 2001 johnson 150 weak spark!!

The testers sell for less than 10 bucks at any auto parts store. But in a pinch, you can make one out of a piece of wood and two nails. It is very clunky, but will tell you something at least. Drive the nails in and bend one to make a 7/16" gap with the other. Connect one side to ground, connect the other side to the plug wire in question. Spark should jump that gap, with a strong blue snap. Personally, I never felt from post number one that you had "weak spark". I think your problems are in the optical sensor part of the ignition system. There are problems with the sensors. But then again, I am not there, and have no definitive test results to go on. What...powerpack and stator...at least 400 bucks, easy....Yes you can disconnect the harness. That will eliminate the key switch question you had. If it starts, you will have no way to shut it down, except by choking it with rags, or re-plugging the harness right quick. Have water on it for all these tests. The tester with the red knob is the type I use. Google Image Result for http://corvetteactioncenter.com/tech/diagnostic_tools/726_06.jpg
 

wilson750

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Nov 22, 2008
Messages
287
Re: 2001 johnson 150 weak spark!!

The testers sell for less than 10 bucks at any auto parts store. But in a pinch, you can make one out of a piece of wood and two nails. It is very clunky, but will tell you something at least. Drive the nails in and bend one to make a 7/16" gap with the other. Connect one side to ground, connect the other side to the plug wire in question. Spark should jump that gap, with a strong blue snap. Personally, I never felt from post number one that you had "weak spark". I think your problems are in the optical sensor part of the ignition system. There are problems with the sensors. But then again, I am not there, and have no definitive test results to go on. What...powerpack and stator...at least 400 bucks, easy....Yes you can disconnect the harness. That will eliminate the key switch question you had. If it starts, you will have no way to shut it down, except by choking it with rags, or re-plugging the harness right quick. Have water on it for all these tests. The tester with the red knob is the type I use. Google Image Result for http://corvetteactioncenter.com/tech/diagnostic_tools/726_06.jpg

Thanks Daselbee, I will try that spark plug tester with the wood.I ordered the optical sensor and should have it this week to try. Trying to find a oem service manual isnt happening.I searched and came up empty.
 
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