A bigger generator will do the same thing. When any load kicks on and off you'll get a surge I just want to soften it.Why do you think they recommend surge protectors for electronic equipment? I just want to build a surge suppressor on a larger scale.
You have a misunderstanding of what a typical surge suppressor does. It protects loads, usually electronics, from over voltage transients. It does not supply power to make up for line voltage droop for loads greater than the power source (generator in your case) can supply. While capacitors can store energy the size needed to compensate for all but a small line voltage droop would be huge. Perhaps a specially engineered combination of an huge inductor and huge capacitor would do but it's not the right approach. As others have suggested a UPS system will do what you need. The mechanical approach would be a large flywheel rotating mass on your generator. The surge power would be supplied by the inertia energy stored in the rotating flywheel.