It's worked perfectly on about 6 engines for me. No, that doesn't mean it will work perfect on every engine, but it's a whole lot more reliable than any Perry pump or fuel regulator that I ever tried. I pulled my hair out with several Perry pumps on several different engines. Never could get one to work the way I wanted. I know others have reported success. I just never found them worth the trouble.

When running a Cline regulator, I have always ended up running my needles out about 1 turn richer than where it was tuned before I installed the regulator. It is a vacuum demand regulator, and there really isn't a whole lot of vacuum going to the regulator. So, you need to open your needles a little bit more to make it flow the right amount of fuel. The guy (Bill) from Cline told me this back when I bought my first one. I have always had great luck by simply ignoring where my brain THINKS the needles should be and just tune them to make the engine run good. No assumptions. Just tune it.

YMMV