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Small Engines (Lawn Mowers, etc.)/resistence in high tension lead


QUESTION: we have a Husqvarna 125 stick edger that will only run properly when you add a in-line spark tester on the unit.
take it off and it starts breaking up from an ignition miss.
How can we add resistance to the system?

ANSWER: Make sure you use an NGK Bpmr6a spark plug.  GO GET A BRAND NEW ONE!!!  I spent many hours troubleshooting and it was a bad spark plug.

You can try a Champion RCJ8Y...MAKE SURE YOU USE THE RC...this is a resistor spark plug.

FYI, we have had the same problem with several Husqvarna.  We have been able to open the spark plug gap really wide on some model to get them to run.

First, try moving the ignition module back, increasing the air gap, as far as possible.  It won't be much but is should move a little. Second, start increasing the spark plug gap and see if you can get it to run.

Let me know what happens with the new spark plug(s) as we have been searching for solution to solve this issue.


---------- FOLLOW-UP ----------

QUESTION: Good morning Eric,
I have tried all of your suggestions and still have an ingition problem unless i run the unit with an in-line spark tester installed to, I assume add resistince in the system. We have had this problem on other machines and haven't had any good results, but then didn't know about moving the ingition module either.
Will let you know if any thing futher helps.
Thank you so much for the help.

I called Husqvarna but all they told me was to use the OEM spark plug the parts list recommended.

I have, and only use the plugs they list for the equipment model number and am still having the same problem you are having.

Please let me know if you find a solution as I am looking for a solution to solve the problem.  I may try using a different ignition module from a different piece of equipment but finding one that fits could be like finding a needle in a haystack and will take a lot of time as I will have to dis-assemble various machines to see what might fit and work.


Small Engines (Lawn Mowers, etc.)

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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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