Boy! Never would have guessed that! The throttle on this one opens all the way, and the coils are fixed in one spot but, they have 2 wires on each coil that go to a small electronic box on one of the shields. So, I'm pretty sure it's a 22 HP. But here is a funny thing, after getting it all tore down it is no longer locked up. What I found was one of the exhaust valve seats had fell out and bent one of the push rods. How that kept it from turning over I'm not sure. But the cylinders and all the rest look pretty good so I think I'll find a head and rebuild this engine instead of buying another one.