Chuck, I had two of the 40s and hated them, I had one of the 51s and it was OK. I am still using the G-20 and it is OK but the SK 1.30 is a lot better, I just feel that after all these years ST would have come out with a better carb because when you change that they are really good engines. Those .40s just really put me off and the carb on this 2300 could use some replacing too. I keep hearing good things about them but???????