Motor Capacitors: Troubleshooting & Replacement

Created by Gabriel Izzo, Modified on Wed, 10 Apr at 2:21 PM by Gabriel Izzo

**Capacitor Safety Reminder**

As with any electrical device, disconnect the power to the motor before servicing it and discharge the capacitors before handling them.  

Please refer to the following article link for complete instructions on safely testing start and run capacitors:

Removing the Capacitors from the Motor Housing

Both the start and run capacitors are located in the capacitor covers on the outside of the motor housing. 

To more easily access the capacitor cover screws, the saw can be tilted to one side or the other to help allow clearance for a screwdriver. 

The easiest way to remove and replace the capacitor covers is to slightly loosen two of the screws on one side but not remove them completely so they can be used to align the cover again afterward and then completely remove the two screws from the opposite side of the capacitor cover to get it loose enough to slide over and remove the cover. 

Once the capacitor is out of the cover, remove the connectors from the capacitor. This may be easier to do by using a pair of pliers to pull the wire connections from the two capacitor tines/prongs. 

How To Test Your Capacitor

Please refer to the following article link for complete instructions on safely testing start and run capacitors:

You can test your capacitor using a high-quality electrical meter. 

The unit of capacitance is microfarad. Capacitors are labeled with what microfarad value (abbreviated mfd or uf) they should be. If your electrical meter displays a microfarad value that is too high or too low, this is a sign that your capacitor is bad.

Before testing your capacitor, be sure to short across the terminals with an insulated handle screwdriver. This will help you remove any stored power. 

The capacitor value needs to be within the labeled range for it to be considered functional. 

If you have more than two wires going to the capacitor, the wires that are paired together on one side must always be paired together.

Replacing the Capacitors

The new capacitors will be labeled as start and run capacitors and will be of different physical sizes. When installing both the run and start capacitors, connect the wire connections to each tine on the capacitor on the same sides that they were installed from the factory, using the labeling on the capacitor as a left-to-right reference. 

Once the capacitors are fully connected, put in place the capacitor cover gaskets and covers and use the two screws left installed to easily align the cover and then fasten all four screws. 

Test the motor by attempting to start the machine and verify functionality. 


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