I 'm not a CEN owner but I'll through in my 2 cents. I didn't see anyone mention the exhaust. If the exhaust is leaking it will do all the things that was described. it won't stay running or won't evenstart even though it sounds like it is trying to start. if the exhaust has a leak it won't be able to push enough fuel to the motor to keep it running. I would say check the manifold at the engine and any couplers that there may be. make sure the exhaust is airtight. maybe this will help. Good luck.