Elkay Bar Faucet Drip

I have an Elkay bar faucet with two quarter turn handles. It was installed in 1973 and has just begun to drip on the hot water side. I removed the handle and the crown nut but cannot get the cartridge to budge. It appears to be plastic so I haven't tried too much force on the metal stem. Any suggestions?

Yes, use MORE force. But have a new stem before you do because you CANNOT repair them.