No worries,
I just had a thought... you have plumbed the decomp into the crank case?..... I think that
may give you drama's as well, as they work from carby side vacuum; in the crank case, it pressures up after the inlet port closes....
You might have to "man up" plug the case hose and take the decomp off.. if you can't fit the hose to the carby inlet as per STD G3 arrangement.
I hope it goes well!
