General Product Question
Have model 435 chainsaw. Not getting spark. New ignition...
General Product Question posted October 21, 2015 by Roman Pawlowski
1059 Views, 9 Comments
Question:
Have model 435 chainsaw. Not getting spark. New ignition module, all gaps to spec. Question is: there are 3 wires to the module: spark plug wire, and 2 wires that are connected internally: one to what looks like a wound spring and the other just terminates from what I can tell. Obviously they have something to do with spark generation. What are they for and is there some adjustment required ?
Answer
There should one each black and blue wires heat shrinked into a cable assy. The black is grounded at coil and Blue which is kill wire is connected to terminal on coil. This cable leads back to the on/off switch. These two wire should not be connect together If you are near zero ohms reading with the blue not connected to the coil then you may simply have the on/off switch in the off position or there is short somewhere.
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Ohm meter readings checkout as per your direction.. On to plan B . Still do not get spark when pulling plug and cranking with plug properly grounded. Is there another way to check for spark ?
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Roman,
Just disconnect the control wires and remove them from the coil, or tuck the wires out of the way with the flywheel. Put the starter housing back on and pull the cord, again checking for spark. If you still have no spark, pull the boot back at the spark plug and make sure the High Voltage connection inside the rubber boot is making good contact with the High Voltage lead, you may need a new High Voltage connector if its broke or corroded or missing. If you have a good conection at the High Voltage connector and still No spark, then you have a bad ignition module.
Also Do Not try to run the chainsaw with the control wires removed or disconnected because you will not be able to shutdown the Chainsaw in a conventional manner with the "Off" switch disconnected.
I hope this helps, and please let me know If you need any additional information on the Model 435, I can check the one I have in my shop, If you need real numbers for a resistance check.
Karla
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Karla, Just remember here and can verify it since you a 435 at hand. Is the coil laminates grounded directly to the cylinder or is there a grounding strap like on the Poulans? If it does have then the grounding strap that could be missing.
Eugene
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Roman.
Just one more thought on Ignition coils, resistance checks are OK to perform but If your Not getting spark after performing my previously stated paragraph, then the coil is bad. Coils can test good with resistance, and still be bad this is because the coil inside that black moulded ignitition module there is an electronic circuit, and there is no easy way to test that electronic circuit.
A substitute Ignition module is the only way to prove that there is something wrong with the first ignition module.
Karla
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Thanks Carla. Will try suggestions. Also, ign coil has been replaced previously.
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Roman,
I understand that your ignition coil was previously replaced. I have been there and done that, and it is very frustrating. Remember that most new coils are made by machines and never touched by human hands, and yes they were probably factory tested by another machine, before being shipped.
Here is a diagram, which I just put together which may help understand a little more about ignition modules. See attached file.
Again, I hope this helps, and please let me know what you discover.
Karla
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Roman, and Eugene,
I just received Eugene's suggestion to check for a ground connection to the engine cylinder, and Yes many engines including Husqvarna's have a small grounding strap usually located behind the flywheel and sometimes difficult to find, its only about an inch or so long and can't be readily seen.
But, before you go removing your flywheel looking for the grounding strap, here is another simple test. Using the diagram that I just recently sent you and a thin piece of wire about 6 inches long, like lamp cord wire, strip back both ends of Insulation and fasten one end to the terminal marked ground for engine in the diagram, and connect the other end of the wire directly to the engine cylinder or base of the spark plug. Route the wire out of the way so it won't get hit by the flywheel, and re-install the starter housing. Perform your spark test again, and If you now have spark then Yes you have a grounding problem to the engine cylinder.
Thanks Eugene for the thought to pass along to Roman.
Karla
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Roman,
I just checked the IPL drawing for a Model 435, and there is No grounding strap required on this model, Since the Ignition Module mounts directly to the engine cylinder. I should have remembered that one since I did remove my Ignition coil back in July but I forgot that it was directly fastened to the cylinder, so grounding should not be your problem.
Please keep in the loop as you investigate what is causing the problem
Karla
PS. I assume that you do have a good spark tester? I would also suggest that you test your spark tester on another piece of equipment to make sure that it is really working. I once had an engine that I knew it had spark, and tried to test my spark tester, only to find out my tester was bad, It definitely had spark since the engine ran. Lol but a learning experience, check your test equipment too!
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