Homelite 33cc NO SPARK

[Wild Bill]

Hello, new guy here, but forum familiar, as they are great and assorted ones have helped me over the years to keep things running

MY issue is NO Spark, I know all the things to check and have been on you tube and anywhere else to look but so far nothing works

Here is what I have done so far, took saw apart to clean it. It sat for several year in the shed unused. so I checked for fuel and spark, I had emptied the fuel tank after the last use years ago and ran the carb dry. pulled the plug wire and the kill wire, grounded the plug on the engine and pulled the starter rope, no spark, hmmmmm

I had cleaned it up real nice, got a new carb, a new spark plug, a new coil, new fuel lines, checked all the gaps and the result was no spark. Yes, I had the kill wire off the coil.
I did all kinds of troubleshooting, rechecked all the gaps, plug and coil. I even had the dealer I got the coil from to send me a replacement coil, still no spark.
Something is preventing me from getting spark, this is a simple ignition system, just a coil, a spark plug and flywheel with strong magnets in it. It should spark but it does not
Suggestions please, I hate to toss this thing it has døne a great job for 10 years and suddenly this issue.

 

[Bob Hedgecutter]

If all parts are correct and attached properly- is the earth strap wire with the crimper on eye in place under the top bolt of the new coil and is the other end also attached with no breakages within the system?

 

[Wild Bill]

I never checked the other end of the ground wire, will do so tomorrow AM. I thought just bolting it to the cylinder was plenty of ground.

From my boating days when ever we had an engine or electric problem the first thing we did was to check and clean all grounds

 

[Wild Bill]

OK I took the saw apart enough to get at the other end of the Ground wire and found Both it and the kill wire are connected into the kill switch.
I checked both wires for continuity and possible shorting between them or in the switch itself and found all was correct. Cleaned every place that makes a ground between the coil and cylinder so they have nice clean grounds.
Put it all back together and reinstalled the new coil, set the air gap with a credit card and still NO Spark!!
This is a big PITA Puzzle.

 

[Bob Hedgecutter]

Put it all together, all wires connected, put the kill switch to RUN and test again.
Why was the coil having to be replaced?
Are the magnets still good on the flywheel?

 

[Wild Bill]

A correction for above, I set the air gap with business card, not a credit card.

I replaced the coil because it had no spark. The OHM reading resistance was hi too

The flywheel magnets look ok and they are powerful too

 

[Bob Hedgecutter]

Okay- as you say- pretty simple system- so something simple is not working.
If you are sure you have the correct parts and that are correctly assembled- try finding another piece of electrical cable-bare the ends of it, wrap it around the threaded section of the plug and attach the other end of the wire to the saw cylinder- jammed under a coil bolt for instance.
This proves effective ground of the plug for testing.
If that still produces no spark- willing to bet there is a break either in the HT cable that runs from coil to sparkplug- or the spiral spring/sheet metal collar designed to be a firm push fit on the top of the spark plug is broken or not making contact with the internals of the cable.

You are using the threaded cap on top of the spark plug? It is not just exposed 3mm thread on top of the plug is it?

 

[Wild Bill]

I am just about to throw this thing in disgust.
All I think is that I may have 3 defective coils. This morning for kicks and grins I pulled the flywheel off for no reason other then to look behind it and make sure the flywheel is solidly grounded to the crankshaft.
Has anyone come up with a sure fire way to test a coil and see if it will make a spark plug spark. A magnet drawn across the coil pickups and then suddenly pulled away cause an electrical circuit and then a drop which in turn makes the plug fire

 

[Bob Hedgecutter]

I an willing to bet the coils work and everything else works- it is just not working together- due to something either not making a direct contact- or something making a contact that shouldnt be.
Inline spark testers are good- no point flogging a dead horse if electrical impulse is not getting from coil pact to the spark plug.
I still think- IF ALL else is correct and installed correctly- slide the rubber cap that covers the spark plug back down the lead and ensure the contact that fits the top of the sparkplug is aligned- is a tight fit to the top of the plug and the other end is making contact with the electrode within the HT cable.
When "testing" for spark via a plug balanced on top of a cylinder loose and trying to maintain enough control to actually see any spark- it is entirely possible you are not rotating the system fast enough to create a spark- too slow in the rope pull.
Inline spark testers mean you can pull the rope as you should- like you mean it.

 

[Wild Bill]

I have cleaned the area the spark plug screws into, it is shiny now*-+
I am spinning the flywheel with my drill motor as fast as it will spin
I am holding the plug down against the of of the shiny cylinder with teeth gitted, Even though I know if it suddenly works I am gonna get bit

 

[Bob Hedgecutter]

You have the drill motor running in reverse eh?

 

[Wild Bill]

Had to spin in the direction it would normally run, yup. For kicks I did it both ways, no diff.

 

[Bob Hedgecutter]

The coil electrode with the bolt through it- almost looks to be contacting the flywheel?

 

[Wild Bill]

That is the bottom coil mounting bolt and there is a 10 thou gap between it and the flywheel

 

[Wild Bill]

I was just watching a Stihl Shop Guy installing a new coil on a Stihl Chainsaw and he said that the coil should have a plastic or non conductive washers on the two mounting bolts between the coil and the cylinder. He mentioned that the coil can be grounded out by the kill switch to turn it off.

My Coil is bolted directly to the cylinder, could this be my problem?? That would require both non conductive Bolts and washers.

 

[Bob Hedgecutter]

My Coil is bolted directly to the cylinder, could this be my problem?? That would require both non conductive Bolts and washers.

If that were your problem- the coil would be factory mounted to the plastic case of the saw from original.
Part of the system must be live (the contacts to the flywheel face) and part of it earthed to ground (cylinder) or moving the kill switch would have no consequence.

 

[Wild Bill]

Is there a special non conductive bolt or a bolt coating that will not conduct electrical current???

 

[Bob Hedgecutter]

Is there a special non conductive bolt or a bolt coating that will not conduct electrical current???

yeah its called heat shrink or liquid insulation.
But you dont need either- your coil bolts to the cylinder so it is grounded to it, with standard steel bolts and as it came from the factory. If the coil were bolted to the plastic case (like saw Husqvarna 350 models) there would be a metal grounding plate from one bolt hole to the engines metal components to complete this grounding.

Something is incorrect within your system- either incorrect parts or incorrect assembly- or a combination of both- but the mounting bolts for the coil is not one of them.

 

[Wild Bill]

Something is preventing the coil from firing the spark plug!!!!

 

[Bob Hedgecutter]

Something is preventing the coil from firing the spark plug!!!!

Exactly- something is wrong- mounting bolts are not it.
Flywheel and coil not matched- incorrectly installed- stray earth within the wiring system- bad plug/plugs- incomplete circuits.

Something went wrong and it caused you to replace the original coil- subsequent coils also did not work- maybe the coils are not the issue?