Where do you spray ether in a Ford E-450 motorhome? Also where is the air intake duct located?

Where do you spray ether in a Ford E-450 motorhome? Also where is the air intake duct located? - 1

You don't unless you want to shell out the cash for a valve job.

How new is it. A modern fuel injected engine should not need ether to start it no matter how cold it gets.