It's a 160cc going by the spark plug position and decompression valve. It needs the fan replaced too.
The red toe cutter base and decompression valve ( zip start) combination places it as an early 1970s utility model.
Hope you find the necessary bits to get this back on the road. Nice model.

Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!