Unfortunately, no. If you have to push start the fan every time, for example, well, that’s going to get old fast and lead to greater damage to the condenser unit (outside AC unit).
Like a battery, capacitors can’t be fixed, only replaced. A weak capacitor may do its job for the most part, but by leaving it in, you will be forcing the fan motor to put in more effort to compensate for the capacitor. This will eventually overwork the motor, causing it to fail.
If your unit uses a dual run capacitor, you also risk damaging the compressor, which will cost you over $1,000. (See compressor price range in “Prices” section above.)
You should replace the weak capacitor as soon as you can.