Well I bought one from Langdon's and mounted it on the 235 in my C-10. Starts and runs great.............OK the bad part. When I turn the engine off, the carb drains dry in a matter of minutes. Looks to be draining in the secondary and leaks out the throttle shaft and down the intake. I've cleaned the needle, reset the floats and checked the floats for boyancy..........all good. It still leaks. There is a power valve at the bottom of the fuel bowl, could this be the problem? What does it do? Thanks in advance.