Inliners International Forums General Discussion Hi Performance 292 with Offy 3x1 = .080 Jets Still Too Lean??

I set up a offy 3x1 a number of years back and did not have your exact issue, just really poor drivabilty and over rich problems (giant jets which caused awful idle and off idle issues). A few years ago, Inliner K. Patrick Smith wrote a pair of articles on dialing in multiple Rochester carbs. Pat was the longtime crew chief for Dyson racing and one of the best engine minds I know. His method is a bit of a pain but I did it and got a 261 motor that ran like dog doo to run pretty good. His articles are on the Stovebolt Engine Company website. You might consider starting there. I assume you are running some kind of heat to the bottom of the manifold correct?

If it turns out that you are running the carbs out of fuel, just changing to 3/8 line will not solve the issue. You have to change the fuel tank pick up to a 3/8 pick up (using an adapter fitting defeats the purpose of the larger line as you are still restricted by the 5/16 pick up.) The next problem area will be the mechanical fuel pump. You need to find one that uses a real 3/8 inverted flare fitting, or you will have to carefully modify the pump (if the casting is thick enough) to drill and tap for a 3/8 fitting. Also, those carbs do not like a ton of pressure, like 6 max, a little bit lower would be better.