You will need HEAT to remove the 2 plugs. I did 3 OFH's at the same time since I had to borrow a torch. Idk if a propane torch will get hot enough as the plugs have a threadlocker on them and you will mess them up trying to do it with a simple Allen wrench or ratchet with an Allen socket alone. I cleaned mine up in diesel fuel in a oil drain pan with a parts cleaning brush. Had everything apart and lubed back up and never thought about needing to replace the spring(s) or plungers. I washed it with Dawn soap and water and it is on the motor i am building right now.
Pictures are worth 1000 words so here is 3000
Marty

Yeaaaaaa I figured these were gonna have to come out but I was hoping not. Ok thanks, found my next weekend project .

I disassembled mine, cleaned everything in an ultrasonic, and re-assembled with a couple new parts. If your pipe plugs are corroded and you want to replace them be aware that they are British Standard Pipe Taper (BSPT). Do not try to use regular National Pipe Taper plugs, you'll ruin the threads. The OE plugs are still available. No need to replace the plunger. The spring is still available and cheap if you want to replace it just for piece of mind.

Solid, thanks! Adding this to my next parts order