BroncoII4x4.com

Hello, I am new here. Been workin on rigs my whole life almost 40 now. One thing I have always had trouble with is after market carbs. I just bought my 17 year old son a 84 bronco II and the guy we got it from put a 500 cfm holley and an after market electric pump on it, which is pushing 4 to 7 psi, and it is having some issues.

First off, I am sure this is way more carb then we need, it seems to run great but once it has been running for awhile maybe 15 to 20 minutes it starts to run rough and sputter then die. At this point it has to sit for awhile before we can start it up again.

The fuel pressure seems to fluctuate a bit when it starts to run rough but I am not sure the pump is the issue. Filters are all new, and gas is clean. It also hesitates a bit when you give it some gas, almost dies sometimes.

I would love to find an original carb to rebuild so I wouldn't have to mess with jetting and tuning this one but I am willing to give it a go.

Please provide any thoughts you might have. I am grateful for these forums and to anyone willing to share their opinions.

THANKS

Is your fuel line close to a heat source? Sounds like vapor lock..... What about the choke is it working properly? I would check for vacuum leaks and do a timing check just for shits and giggles.

Same as above.

The 500 doesn't need an electric fuel pump either. The stock mechanical one will supply everything it needs and takes one more thing out of the equation. (think KISS principle)

Secondly, they rate the 2150 as one of the best carburators out there.. If it were me, I'd get back to basics. You can spend you time on the Holley and maybe get it running right, (you may have to get smaller jets) or get a 2150 from an early 4x4 BII or Ranger and tweak it right. The 2150s are also made for supplying juice reliably in 4x4 situations, the Holley is for street use. The 2150 when running properly besides being quite reliable will also deliver performance and mileage. You should be able to get better than 20mpg on the highway in 2wd.

Don't get me wrong, I love Holley carbs in the right application and when properly matched to the engine.