With the issues that you are describing it could be a few things. The first thing that I would do is throw a spark checker on it and test for good CONSTANT spark, that will narrow it down between spark and fuel. You can take the carb. apart and clean it and rule out the fuel issue or see if that gives you any change. It can also be the plastic cam issue although your symptoms aren't exact for that issue OR time delay module. What year is your 425 to know if it has the plastic cam and how many hours are on it?
Where in PA are you located?
Dan
Where in PA are you located?
Dan