The problem I used to have with 4150's was with the metering plate gaskets
that would eventually swell and cause problems. Perhaps they are made from a
more impervious material now. They other problem people frequently encounter
when messing with these is not torqueing the fuel bowl screws tight enough;
use a big screwdriver and crank hard.
I never had a power valve failure, but never had a wild engine either.
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