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Old Jan 15, 2013, 06:19 AM
DarZeelon is offline
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Israel, Center District, פ"ת
Joined Nov 2003
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Murcielago,


Your assumption is correct.
Engines that use a fuel-pump, like the OS.70 Ultimate, neither need nor use a pressurized fuel-tank.

The only reasons a pressure fitting might exist on the Ultimate's muffler, is if it is use to burn-off excess oil (connected to the crankcase breather), or if it is a carry-over from earlier Surpass engines.

Earlier YS (Yamada) engines differ, since their pressurized fuel-system requires the tank to be highly pressurized (over 5 psi, compared to ~.3-.6 psi for muffler pressure).
This is done by timed pressure from the crankcase - not from the muffler.
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