Question on electrical module

[Ed Kennell 41,384]

This is not a WH part and if I am breaking any rules, let me know.

 

I bought an as is string trimmer  at an auction for 4$, and it looks in good enough shape to attempt to get it running.

 

The part in question is an MTD 792-10527A module from a Bolens string trimmer.

I don't have any spark.  Is there any way to test with a OHM meter ? I get a dead short between the two pick-ups.

What should the "gap" be set at ?

I'm sure SOI has the answers.

Thanks, Ed

[Save Old Iron 1,571]

I get a dead short between the two pick-ups.

 

 

 

Ed, I haven't had to do any weed wacker fixin' in 20 years. Assuming you have a standard magneto which will be energized by a magnet on the flywheel, I can see the need for at least one lug on the magneto body to be leading off to a kill switch. Make sure this lead is not grounded when you have the kill switch in the RUN position.If you do have two wires leading from the magneto, they probably both go to a switch that shorts out the primary coil of the magneto to stop the spark from the secondary. Remove both wires from the mag unit and try to get spark once again.

 

Beyond that, make sure the magneto body (metal mounting tab) is grounded to the engine frame. Pull back the spark plug boot to make sure the spark plug wire is not corroded off the metal clip which grabs onto the spark plug.

 

Magneto gaps usually run about 10 thou. Maybe download a manual for the wacker, they might have more specific settings, but 10 thou should at least get you a spark if the magneto is good and the kill wire is not grounded.

 

As far as resistance measurements are concerned (and I'm guessing here) the spark plug terminal to ground will probably be in the range of 8 - 15K ohms ????  The two lugs connected to the kill switch (the primary coil in the mag) may have only 100 or so ohms. Make sure the kill switch wires are removed from the mag when you make this measurement.

 

Again, a service manual off the internet may be a good place to start.

 

Best of luck.

[Ed Kennell 41,384]

Thanks SOI,

  I,ll get back to the trimmer later.  Gotta go work the horses now. We got 6" of the white stuff this AM. Better go before the sun melts it all.

Ed