Intermittent Spark

[picman59]

I have an intermittant spark issue on a Johnson 60ESL70B. There is at times no spark on any plug. A friend gave me a generic test proceedure to follow. while I was looking over the engine all I looked at was the inline fuse, I tightened down a purple wire with a ?? color stripe that I later traced back to the choke, pulled the boot off the coil wire and wiped the dirt off the coil wire that goes to the block of electrical connections. My helper tried to start the engine while I was off doing something else. The engine was running when I came back. Now this morning, it does not spark. This happened once before-running fine and then no spark.

Is it possible for the coil to only fire intermitenttly or if it stops it is dead? Can I remove the coil wire from the distributor cap and use a spark gap guage to test that it at least fires?

 

[tashasdaddy]

Re: Intermittent Spark

several pages of test here. http://www.boatpartstore.com/page28.asp

 

[picman59]

Re: Intermittent Spark

I actually have that test sheet. I don't think I can use my spark gap tester on my coil. The coil wire is one pc from the coil up to the distributor. I will have to figure out how to modify the plug end to something like a probe end to get into the coil wire-unless there is an adaptor. I do not have a tester for DVA. I will have to borrow one if needed.

I really don't think it is the coil because it should either work or not. I have replaced the rotor this year and everything else under the flywheel looks up to snuff.

 

[picman59]

Re: Intermittent Spark

I know it has been a bit since I posted but here are my results for testing the ignition system following the procedure in the link above.

Step 1. Spark is intemittent from the coil. When the coils does spark, I have spark at the plugs.

Step 2. There is more that 9.5 volts at the purple wire on cranking.

Step 3. Zero voltage and simultaneous no spark at coil. I think I was confused by the term DVA voltage. I am assuming that DVA is just another term for ignition box, CDI, amplifier etc. So I am testing for 200 volts DC current. I am attempting to test votage when I see spark at the coil. It has been a long wait. If I can get spark and voltage at the same time, then I have definitively proven that the amplifier is bad? But I think that has been proven already. I need to make sure before I spend that kind of money. The wife would string me up if it was not bad.

Am I on the right track?

I did notice there was electrical tape on 3 wires that went up to the wire terminal. Upon removal, I found the blue wire was missing the coating on the wire. The wire looks a bit corroded but then again it does not look like copper wire either. I was thinking that I could splice that wire but if it was the culprit, I should have at least some voltage coming through.