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Craftsman 20" chain saw

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11-11-00, 10:55 AM   #1  
Does anyone know if the clearance gap between the flywheel OD and the ignition module is critical? I have a poor spark on the subject chain saw and noticed that one of the ignition module mounting screw holes is elongated suggesting adjustment. Would appreciate a typical gap value for this adjustment!

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11-11-00, 05:42 PM   #2  
Hi:Ed Hickey

The air gap is what that space between the flywheel and the magneto is called. It is a critical setting.

The distance should be about .0125 thousands.
This is about the thickness of a very thin business card.

Plastic or any none metalic but flexible material of that thickness should be placed between the flywheel and the magneto and the adjustment set.

Lightly sand off any rust on those parts, spray with wd-40 and wipe them clean.

Poor spark can also be caused by several other conditions. The spark plug. The plug gap. Corrosion in the spark wire cap that fits on the spark plug or any ignition connections.

You didn't mention if that setting has ever been altered for any reason?

Accurate Power Equipment Company.
Small Engine Service and Repair Technician.
Personal Quote:
"If it ain't broke, don't fix it!"


The air gap measurement was found to be incorrect in my first posting, as mentioned by Ed. The correct distance is now posted above...:-)

[This message has been edited by Tom_Bartco (edited November 12, 2000).]

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11-12-00, 12:27 PM   #3  
Thanks for the info Tom. The flywheel/ignition module had not previously been modified but when I loosened the ignition module screws, the flywheel magnets pulled it into contact with the flywheel.
I'll adjust to the 0.125" gap and let you know what happens.

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11-12-00, 03:36 PM   #4  
Hi Tom,
I assume that the gap dimension you provided was meant to be 12.5 thousandths of an inch (0.0125")and not 0.125 thousandths of an inch (0.000125"). My measurement of a business card thickness is 0.010"


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11-23-00, 06:44 AM   #5  
Basically, like setting the points in an old car distributor.

Perry Wright
"Relentless" Racing

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