Why did you jet the carb down? the carb is set to run in cold also it must be rich for the heaver cold air, all carbs run rich in the summer unless you lean it ,it never was a perfect system the over fuel in the summer would break down the oil, wash the rings down this is why 100000 mile was the limit on most engines until fuel injection came out and you could keep that perfect 14.2 to 1 ratio and engine life doubled. also remove the catalytic on newer cars and you will get black smoke and burn your eyes at idle. while you got the metering block off put the other jets in you will be happy!