go to the parts store, grab a light bulb socket with 3 wires, like a taillight or something. Grab the suited light bulb, small roll of 12g wiring, and make yourself a 2 channel test light.
One leg to the starter power, one to the trigger, and one to ground.
Now watch and see if it gets brighter when you are trying to start. If it clicks, and both go out for asplit second, your battery, while it has good VOLTS, might not have any grunt.
If you have a jumppack, remove the battery from the equation by removing the ground, and using the jumpack as the battery.
Temporarily also ground the battery engative directly to the transmission casing somewhere.
One leg to the starter power, one to the trigger, and one to ground.
Now watch and see if it gets brighter when you are trying to start. If it clicks, and both go out for asplit second, your battery, while it has good VOLTS, might not have any grunt.
If you have a jumppack, remove the battery from the equation by removing the ground, and using the jumpack as the battery.
Temporarily also ground the battery engative directly to the transmission casing somewhere.