I have a 4 KW generator in my motorhome, and it runs on the unleaded gas that runs the motorhome. It uses about a gallon per hour on full load. I assume that a 17.5 KW "portable" is on a trailer?

I have found with experience that it is important to start the generator at least once per month, otherwise it gets gummed up and hard to start.

The manual transfer switches that I have seen are "break before make" switches, so that it is impossible to send power the wrong way (back towards the utility) or have both generator and utility power coming down the same wires at the same time.

A friend recently got a 25 KW generator installed at his business to run critical operations in case of power failure. I got to watch the install. There was much more to it than I imagined. Different legs went to different circuits, and everyone was very concerned with "rotation". The electricians called in some "generator specific" electricians to deal with the "rotation" issue. I am certain that others with more knowledge than I will contribute.

How are you planning on securing your generator if your place is lighted, and no one else is?