The engine is from a John Deere. I think it was a John Deere 400. I also have the John Deere engine mount that looks like a steel plate. I can provide the spec if needed.
The compression test was done with a cold engine after it has sat for over 2 years. The compression will be higher with a warm engine and lubricated cylinders. The compression test showed 115 and 120 psi.
It has a 1.5" diameter crankshaft.
I bought it in August 2023 as a spare for a Bolens HT20 but the crank is different and I don't have room to store it.