Symtom of rev limiter malfunction?
I have a weird just off idle stumble on my 509 BBC with 750 double pumper. Starts fine, idles fine. As I start giving it throttle, it stumbles and farts a bit. Once past 3/8th throttle, it goes away and runs fine. Almost like it was getting too much fuel as the accelerator pump squirted fuel. Thought it was mis-cammed or mis-adjusted accelerator pump. Still there despite messing with it (changed from pink cam to orange cam). Am thinking I may be barking up the wrong tree and thought it may be ignition instead. Have a very old MSD 6A that MSD converted to a 6T 30 years ago. This conversion added a second box, which plugs into the 6T with a short cord. Into this second box is plugged the chips to limit the RPM. As the engine is brand new, I have not taken it to the 6000 RPM that is the current rev limiter chip to see if it cuts out. Thoughts? Thanks!