No Spark


Old 08-20-03, 06:28 AM
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No Spark

Hi everyone - My string trimmer(older McCulloch) does not have a spark. I'm thinking the problem is the coil. Do these engines have points? How do you test a coil?
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Old 08-20-03, 08:27 AM
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Hello scubagator. Welcome to the Do-It-Yourself Web Site and our Small Engine forum.

It is always possbile other parts in the electrical system can be the cause of a no spark condition. However, before suspecting those parts, lets start with the easiest parts to access and replace, if need be, first.

Replace the sprk plug with a new one. The current no spark condition may simply be because of a defective plug.

Another possibilitity could be a ground. Check the kill switch. Use an ohm meter to test it. Note the results of the test.

Most likely I haven't covered all of the possibilities. The other resident small engine service and repair professionals in the forum may be able to offer additional suggestions, advice & help.

Check back on your question several times over the next few days for additional replies.

Small engine repair parts, generic repair manuals and additional help are all available at all local small engine repair shops and or lawn mower repair shops in your area. Shops and dealers are listed in the phone book directory.

Read all already asked questions regarding engines with no ignition problems, etc and the replies offered in them on this same type of problem for additional help & information. Doing so will provide additional possible causes and the solutions to correct them.

If you need further assistance, use the REPLY button. Using the reply button moves the topic back up to the top of the daily topic list automatically & keeps all communications in this one thread.

Regards & Good Luck.
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Old 08-21-03, 01:03 AM
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Hello scubagator!

Sharp Advice has some sharp advice, lol!

Check those things out first. McCulloch coils do seem to go bad a little more often than most other makes. Problem is that parts are no longer available. Maybe you can find a NOS coil on a shelf at some repair shop though. Or maybe one off a junked unit in a repair shops' junk pile. I doubt your trimmer has points.
Old 08-21-03, 12:30 PM
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Thanks for the feed back. I have changed the plug and ruled out the kill switch. Having done that is what lead me to suspect the coil.

Can the coil be test for continuity?
Old 08-21-03, 09:31 PM
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You can test the coil by removing the kill wire and turning the engine over while holding the spark plug wire very close to the engine block(more of a two man job). If you see a spark, then the coil is good, but if there is no spark, then the coil is faulty. However, coils can be checked for resistance by putting one lead from the meter on the ground (the base of the coil where it bolts to the engine) and the other lead to the wire where it connects to the spark plug. Most coils have a certain resistance that they should stay within. I don't know what yours should be but a good rule of thumb is that it should show some resistance. If there is no resistance, then it is an open circuit. If you can find the propper amount of resistance than you could tell if it has an internal short because it would show not enough resistance. Hope this helps!!!!!!

P.S. Make sure to have the propper gap between the flywheel and the coil and also make sure that the flywheel is clean so the magnets can do their job.
Old 08-22-03, 12:03 AM
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if u have a multi meter... check fo rthe resistance of the wire and the coil... other wize go in the garage so its dark... pull out the plug and leave it pluged in and grownded but make sure u can see the plug... and u will see it spark... just dont make any fires...

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