yomincarr

Hey All,

I have a 5.3 LH6, z06 cam with a 650 Brawler carb. Its always seemed to run too rich though as its smells like fuel and spits gas out the exhaust. I had it tuned twice, once on the dyne where they put in 69 jets, and more recently when they changed to 73 jets. With the current jetting it’s more responsive and runs better then with leaner jets where it stumbled and backfired…Ive been told that moving to fuel injection would help, but that the only true solution is MPI since the TBI setups on the market now can introduce stalling and other random gremlins. Ultimately, how can I fix the mixture issue since re-jetting didn’t seem to work? Is there even a way, since these engines were designed to be fuel injected and I’m back dating new tech? Alternatively Is the carb too small?

Cheers,

ZONES89RS

iTrader: (25)

Just gotta keep at it. You can even use steel brush wires to lean out the cruise circuit

slothman

pictures of the plugs would tell the story ...white center is lean, light brown is perfect, dark brown/black is rich.

Rick Dorion

iTrader: (1)

Do it yourself and get an AFR gauge and go from there. I have the same carb. It runs great after alot of adjusting. Great learning experience.

Everything is adjustable on the Brawlers. The main jets were one thing I didn't have to adjust!

yomincarr

Rick, what size jets are you using? Ill pull some of the plugs and see how they look,

Rick Dorion

iTrader: (1)

The Brawler was rich out of the box. It's very sensitive to idle mix adjustments.

I have mine about 1/2 turn on each corner. Even 9/16 turn out will make it too rich.

I went down two sizes on the primary from stock 70 to 68. I also went down 10 sizes on the idle air speed to fix a lean stumble.

Many hours doing testing.

Everything on the Brawler is adjustable. But I don't think your issue is main jet size.

Doug G

Idle air bleeds for idle mixture and work with the idle air screws. (you will have idle air bleeds AND high speed air bleeds)

Squirters for bog/stumble issue (fuel enrichment when pedal is pushed)

Pump cams also help where/when squirters activate. (like above)

Jets are for driving.

Power valves are for WOT. (and go with jets since they open as vacuum drops to increase fuel)

At what point is your issue ?............ Idle, cruise, WOT ?

AND I second the AFR meter... see your changes instantly.