Hi SR,
long time no hear. I thought the washers only help to achieve a low idle.
Have you checked that the diaphragm is sealing around the edges or the motor isn't sucking in air where it shouldn't such as the inlet manifold. Have you checked the condition of the manifold O rings? That is a known cause.
You should be able to use any washer that fits over the shaft the cam sits on as long as it's about 1.6mm thick or slightly under. That's what I did to one G4 plastic carby and it worked fine. I actually combined two to make up that thickness. It can be more challenging to fit the tiny ball end of the throttle cable back on the cam so best not to exceed 1.6mm. I'd either buy a vernier caliper or borrow one to measure the washer's thickness with accuracy.
Any pics of the classic? So glad you revived him on your side of the planet!
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!
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