Is it mandatory to quickly vent the fuel tank pressure after a flight? Is the regulator supposed to prevent fuel from flowing into the carb when the engine is not running? My ST2 will achive a hydraulic lock if I don't vent the fuel tank pressure within about 5 minutes of landing. Then I must remove the plug and spin the engine over to blow out excess fuel, reinstall the plug and then try starting again. Is this normal?
Am in the process of adding a Schrader valve to the throttle servo so the tank pressure is automaticlly purged as I shutdown the engine. Perhaps this is overkill but it seems like a good idea to me.

thanks
Roy

Yes it's mandatory. The YS engines vreate a very high pressure in the tank as you would know.
When your carb is closed, the engine stops more due to no air getting into the carb anymore, but your idle needle is NOT all the way closed.
You could test this by screwing in the idle needle when the carb is close, althought I don't recommend it as the YS is a bit touchy to it's idle needle settings and you would want to mess it up.
Lot's of guys run a 3rd line with either a plug or a small plastic clamp that you can undo to release the pressure.

I've got the Schrader valve installed. Have yet to start the engine with it in place but it is working perfectly so far. As soon as you push the engine kill switch the throttle servo crank backs up and depresses the valve, purging any tank pressure. If nitro does not disolve the seal all is well.

Roy