The 20* weather here in MN is gonna give you a touh time tuning the engine. Running the Byrons will probably drop your temperature. Ready to run fuels have high oil content which makes them run hotter. Switching to a better fuel will let you lean out the engine, giving it more power, yet run cooler. Might be a good idea to pull the engine out, and make sure its sealed well. Get a new fuel tank and fuel lines and exhaust gaskets. Air leaks are a huge plague in the hobby, and are the easiest to overlook but super simple to fix.