I have a capacitor regulated 50 hz ( 3 kw) generator and need to set the frequency but I'm not getting any readings I can make sense of, at 230 v my multimeter says 1.3 khz and my plug in my plug in meter says 210 hz.

I replaced the capacitor with a used non OEM one of the same value .

I haven't got a tacho.

 

What test equipment do you have? You are probably overdriving the input to your frequency counter. Check its input spec. You may need to use a resistive attenuator or a transformer to reduce the voltage enough to get accurate readings.
If you have an oscilloscope you can use the mains frequency as a reference and adjust the generator using Lissajous figures.

 

What test equipment do you have? You are probably overdriving the input to your frequency counter. Check its input spec. You may need to use a resistive attenuator or a transformer to reduce the voltage enough to get accurate readings.
If you have an oscilloscope you can use the mains frequency as a reference and adjust the generator using Lissajous figures.

I've got a kill-o-watt meter and a multimeter

 

It might be a good idea to check the manuals to see whether your input to the meters is excessive as KeithWalker suggested.