You want to use those bits and pieces to produce (some approximation of) 60 Hz 120VAC (or 50 Hz 240VAC) single phase?
What are your loads? How much power draw? How long do you expect this thing to run for? Is this going to be a permanent off-grid situation?
Lawnmower engines are not designed for long-term operation. I recall seeing somewhere that the design life of an engine like that is a few hundred hours.
The off-grid folks mostly advocate solar generation and a serious storage battery. Integrated solutions are available from brands such as Ecoflow, Renogy, Bluetti, and others. No petrol engine to feed and be noisy and stinky and wear out.