Could a weak spark on a mcculloch trimmer be a duff coil

Is it possible you connected the coil wrong, maybe reversed the wires, just a suggestion.

if you have power to the coil the only things that can be wrong are: -
1. the coil is duff.
2. The HT lead is broken.
3. the plug cap is duff, broken.

Remove plug cap and see if there is a spark from the wire core when the lead is placed near the engine/frame.

If it sparks OK replace the plug cap,. no spark means either the coil or the lead are duff. If you can replace the lead try testing again without the cap. Hope this helps.

Magneto could be dirty, wires could be broken, spark plug could be bad, etc.

I recommend contacting your local authorized service center for assistance.

You may contact the manufacturer, download manuals, check fuel/oil ratios, order parts, find your local service center, and view other resources using these links:

Contact us
What is the correct fuel mixture for McCulloch products Chainsaw Trimmer...
User manuals McCulloch Service

I trust this information proves beneficial.

I recommend contacting your local service center for assistance.

You may contact the manufacturer, download manuals, check fuel/oil ratios, order parts, find your local service center, and view other resources using these links:

Contact us
User manuals
What is the correct fuel mixture for McCulloch products Chainsaw Trimmer...
McCulloch Service
McCULLOCH PARTS ACCESSORIES

I trust this information has proven beneficial.

No. Your magneto or wire could be broken. I recommend contacting your local authorized service center for assistance.

You may contact the manufacturer, download manuals, check fuel/oil ratios, order parts, find your local service center, and view other resources using these links:

Contact us
User manuals
What is the correct fuel mixture for McCulloch products Chainsaw Trimmer...
McCulloch Service
McCULLOCH PARTS ACCESSORIES

I trust this information has proven beneficial.

Yes. I recommend contacting your local authorized service center for assistance.

You may contact the manufacturer, download manuals, check fuel/oil ratios, order parts, find your local service center, and view other resources using these links:

Contact us
User manuals
What is the correct fuel mixture for McCulloch products Chainsaw Trimmer...
McCulloch Service
McCULLOCH PARTS ACCESSORIES

I trust this information has proven beneficial.

I am assuming you held the wire near the engine while trying to start it? If so then you need to either replace the ignition coil or hopefully just the spark plug wire.

If the wire is broken it won't spark either. You can check the wire with a multimeter set to resistance (ohms) and check for infinite resistance, if you get infinite then the wire is shot.

It sounds like the coil is bad.Thanks for asking and I hope it helps

No spark ussually means the coil wire or coil is bad.

the only thing left is the coil that is inside the cover right next to the flywheel with a gap of 10 thousand of a inch a business card will work but a new coil is almost thr price of a new trimmer unless you have a used one