Thermoquad Tuning & Troubleshooting
I agree with the "Feisty Fish"....sounds alot like a dried up accelerator pump piston,
(Assuming you've blown the shooter out with compressed air?)
A worn Accelerator pump shaft (yes they do wear over time...) can allow the fuel to bypass the piston as well - so can a leaking pump plate at the base of the Acc pump shaft.