That restrictor is part #203390 I believe. It was called a bumper and actually came from a different part of the engine. As someone stated you put it in the bypass hole to warm the engine up. I can’t remember if you left it there or not, long time ago. Those motors did have a tendency to have an off idle problem. Like Frank has stated dumping the fuel was a problem inside and was problematic, but we were not allowed at that time to just dump it overboard. I can’t imagine doing it now! It would be nice to bring it around and put it back in front of the reeds with a check valve. The key would be for it not to be consumed until the motor was up at speed. Easier said than done. In ’77 OMC changed the midsection on the motor and that helped with the back pressure issues. Of course it was a different powerhead by then also. It wouldn’t be till 1985 before the thru hub exhaust would help,tune the motor even better. Don would probably remember more about the issues on these motors. Don’t be shy about fiddling with the pickup roller. I believe we would pickup the carb late to improve the blubber some.

Dan in TN