Briggs Engine Shaft size?

[wheeler]

Excuse my ignorance, but what is the shaft size on a 18hp Briggs/Stratton, VTwin Vanguard 2001 model. It's on my 2001 MaxIV. I'm in the market for a new engine and I want to make sure I get the right shaft size to hook up to my clutch. Are they pretty standard as far as size. Sorry, but I'm not sure the proper way to measure it.

[amphibious drew]

An 18 vanguard in a max IV from the factory would have a 1" shaft with a keyway in it. The keyways are standard sized. If you get another motor with a 1" shaft you should be able to reuse your key and clutch with no issues.

[wheeler]

Thanks AD.