I think TET was referring to the R44, not the cessna.
I'd agree withthe others- careless installation has pulled a shred off which was disturbing venturi airflow.
SU carbs on cars were deemed to have "needle-flutter" caused by airflow when the venturi was wide- this caused unstable mixture and prevented the carb. from meeting emergent emission standards. the "cure" was to spring-bias the needle so that it always pressed against the jet,thus stabilising it....a flawed fix, 'cos the constant "sawing" up and down ensured both jet and needle wore rapidly.....not so bad on wide venturi openings, but a bugger when the needle was fully down and the wear had a dramatic effect on the size of the gap twixt needle and jet.
I digress (as usual
) the shred of rubber would not only thrash around wildly, but would also elongate considerably, as this foam has a considerable amount of elasticity as one of it's basic functions.
Earlier posters are bang-on.....careless installation. and, yes, they're quite likely bog-standard automotive parts probably same with oil and fuel filters. anyone thinking otherwise hasn't a clue about development and tooling costs.....the huge markup increases the distributor's profit and gives enough extra to also pay the premium for product-liability insurance.- Cynic? moi?