With the Williams engines I have I use 6 amp 50 volt bridge rectifiers in them instead of the reverse circuit board. I have a pair of powered F-7's that I did that to because they would not start in the direction that I wanted them to start in as I double head them. I have run the F-7's for over two years that way without problems.
Just make sure the voltage rating is good for your electronic parts if you use them.
Lee Fritz