[(F5)]

With a centrifical governor it should progressively open to some extent. The addition of a spring adjustment will just add preload. Haven't pulled a later unit apart.

I'm guessing snowmobiles are pneumatic, from my tiny experience there they tend to open rapidly depending on pressure bleed, at least on my Cheetah engine that was the case until I converted it to servo motor.

First check for free play, if there's heaps airflow can open the valve. Then check all the balls and correct spring arrangement.