I build my carbys in front of the telly at night and I haven't come across a non working decomp valve in ages the ones I seem to end up with are trashed beyond repair. The reason I started looking for these valves was because yesterday a mate brought his Victa 24 over because it had a spark plug in the decomp and he hurt his shoulder trying to start it. It had had the spark plug in there since he bought it but it had begun to aggravate his shoulder recently