Cutting particularly thick materials or running a jigsaw at a low speed for an extended period can place too much stress on the motor and cause the tool to overheat.
You may also notice an electrical burning smell.
These signs indicate that the tool is being overworked and its internal fan is not able to cool the motor fast enough.
When the jigsaw runs without load, the fan is able to efficiently keep the motor cool. However, when it comes into contact with a workpiece, it begins to struggle, which can sometimes cause the tool to overheat.
If this happens whilst you are using your jigsaw, withdraw the blade from the workpiece for a minute or two, but keep the jigsaw running.
This will enable air to circulate within the motor, cooling it down.
To prevent your jigsaw overheating, make sure that you are using the correct blade and are running your tool at the optimum speed for the material you are working with.
It is also important that you don’t use your jigsaw to cut workpieces thicker than the cutting capacity of your tool (specified in your jigsaw’s manual).