Using SeaFoam

If you are just decarbonizing... pour it slowly into the carb at fast idle or a bit higher.

Since you have a new rebuild there should be no way for it to get into your oil.

It will smoke... ALOT, but it will clean your carbon out in one shot!

If you put it into your oil, make sure to change it soon after... like others have said, it will remove all sorts of build up from your oil system... and you want to get that out as soon as possible. I have seen oil starvation from an oil pump pickup getting clogged as a result of not draining the seafoam... man, that must have been a real dirty engine.

Running it through your fuel system by adding it to your tank will work... eventually. But the directly into the carb works instantly.

Back in the day people did the same thing... except they used transmission fluid, or even water instead of seafoam! (I've done both... but not in years!)