G'day Dan265 definitely keep the poppet valve on C that's the richest tune, going to A or B will lean it out more and with that comes more revs and heat...Try putting brass spacers in the carb (see pic) I've run up to two to bring revs down, yours may have one if so try two,I don't know part numbers or what Victa call the brass spacers but that's there job take any wear out and bring revs down worth a try.. As you have said with the missing black heat shield that would be why the cowling is melting.. Cheers Chris [Linked Image]
[Linked Image]
[Linked Image]