Popping/backfiring of middle cylinders after rebuild
Posted: Tue Jul 11, 2023 12:49 pm
Hello,
I am working to rescue a 92 Seca II that hasn't been run for 12 years. Rebuilt the carbs, new oil , filter and plugs, and started using a fuel bottle with gravity feed and have the air cleaner off. She started right up on choke. Warmed up pretty quick and idled with choke off. Seemed to rev fine. But I noted intermittent popping back though the middle two cylinders, felt like unburned fuel being blown back, not smoke or burned fuel. And popping is intermittent, with periods of clean running and then the popping and stumbling. Any suggestions or thoughts? Blowback past intake valves? Need for a valve adjustment? Thanks for your help.
I am working to rescue a 92 Seca II that hasn't been run for 12 years. Rebuilt the carbs, new oil , filter and plugs, and started using a fuel bottle with gravity feed and have the air cleaner off. She started right up on choke. Warmed up pretty quick and idled with choke off. Seemed to rev fine. But I noted intermittent popping back though the middle two cylinders, felt like unburned fuel being blown back, not smoke or burned fuel. And popping is intermittent, with periods of clean running and then the popping and stumbling. Any suggestions or thoughts? Blowback past intake valves? Need for a valve adjustment? Thanks for your help.