If it was mechanically sound when you parked it, it is unlikely that it is anything mechanical now. If you have a hydraulic cam, I have had plungers in the lifters stick.
Whenever I used to let mine sit for extended periods of time, I always ended up with a small chunk of bowl gasket in a metering passage or dirt in an air bleed. I usually had to pull the carb apart and blow out every passage. I often didn’t get it the first time.
If you had issues with the accelerator pumps, you would see that as a leak or as a non steady stream when you look in the carb(s) and actuate the throttle.
Just curious, do you drain the fuel out of the carb(s) during the off season? Seems like when I changed to draining the fuel from the carbs, I traded pump gas residuals for dried gaskets.
Back when I ran carbs, I made a habit of bumping the fuel pump to gradually bring up the fuel level in the float bowls so that instant pressure doesn’t shock the needle/seat valves and floats. I have stuck a few and even bent that little tab on the float that pushes on the needle.
As icecreaman stated, “go back to square 1” and verify.
Good luck,
Joe
