Thread:

jetting on Holley?

Originally Posted by rpm0414

Another motor question guys-- when I rebuilt my carb I noticed front jets were 72's and rear were 84's. Holley lists this as stock. Wow that's quite a rich secondary? Is this normal for jet boat? Once again the boat thing is new to me so just asking.

S&S is right. You looking at this from the wrong end. Its not that the secondary is rich, its that the primaries are jetted for lean cruize. When the carb is open enough to bring in the secondaries, the PV on the primary side will be open and the jetting will be much more equal.
I would GUESS that this is a vacuum secondary carb, or an possibly an early double pumper. Most hi perf carbs have a closer pri/sec jetting because the power valve restrictor jet tends to be smaller than street carbs. Realistically, most newer double pumpers and hi po carb PVs add closer to 4-6 jet sizes, were as street carbs can add up to 8 or 10 as S&S posted.