Been a while since I removed those plugs. They do not seem to want to budge. Can you use heat on the cover without distorting or discoloring the cover? Any advice would be appreciated. I want to get my electric start to start working again now that better batteries are available.

I removed all the electric start gears years ago. I still have all the parts.

Bob In Fresno.

Thers a rubber oring behind the plug
heat is ok but be prepared to replace the orings as they will probably distort from the heat.
Old brits sells a fabricated tool for removal looks to be a good idea if you really need to leverage them off.
If you bugger them they are all over the net for sale. Commando Specialties even has them in Stainless.
Marshal

No matter what tool you use (Old Britts is good), those inspection cover slots seem to bugger up exceedingly easily....

I use a portable hair dryer to heat the case around the plug, then take an ice cube and hold it directly on the plug. Then I use a short flat bar that fits completely across the plug slot. A quick turn and the plug easily comes loose.