My PV isn't opening. The exhaust valve itself moves freely and it's not improperly adjusted. Appears to be the exhaust valve actuator causing the prob. Any tricks or tips to fix or just replace actuator?

It was working fine and then I let it sit all winter and it worked fine when I first started riding then suddenly one day I lost alot on top end. I currently have it adjusted with no spring tension and it opens as soon as the quad is started, Kills the bottom but at least it's rideable again( I spend most of my time in the red zone. LOL)