"My landlord's old beetle won't start. I'm going to kick it in the arse and see if that will get him started."
If you're going to call the Beetle (I assume it's a Volkswagen) 'it', you shouldn't change to 'him', unless that's part of the joke. (I don't pretend to get it.)
'Would' is wrong if you're using "I'm going to ..." You could say "I could kick him in the arse to see if that would get him started."