Jim,
Try this link to a service manual. It will cost you 5.95 but well worth it. I tried sending my copy but couldn't get it to load correctly. You should be able to get instructions and clearances. Is it running bad or you are just checking? Does your engine have the two barrel carb?
https://subaru-robin.servicemanualvault.com/Subaru-Robin-EH65-Engine-Service-Manual.html