The YS diaphram is used on present day four-stroke engines and is available from YS Parts for about $2 to $3 as I recall. I bought a couple as spares as there was discussions about them getting old and wearing out. I haven't used one of my spares yet. They are simple to replace, if necessary, and are still available. I even asked Richard at YS Parts if I should buy a few more so I would always have a spare. He said not to bother as it was a commonly used part in several engines and would be available indefinitely. I'm not trying to push YS two-strokes. Just like religion and politics, everyone has an opinion. But I do think in Vince's particular application, the YS 61 would simply solve his problem. There are still new YS 61s that show up and the only part that could possibly need attention would be that $3 diaphram.