I'm working on a 77 f250 with a 4350 carb.
it seems to pull quite a bit of advance right at idle. about 35 deg BTDC. It is using the vacuum port from the carb, which I beleive is ported vacuum. Manifold vacuum seems about right and the ported vacuum from the carb goes from about 4 inches at idle slowly to about 18 inches under full acceleration.

As far as the problems it is experiencing... it has a difficult idle to set. it has a flat spot on acceleration ( ie it will pull strong up to around 2500 and then stops pulling (autotrans kickdown was unhooked). bogs on light acceleration. basically just hard to adjust anything.

Anyone have instructions on tuning this carb or an answer to this problem? Where can I find info on this stuff?

 

Is the accelerator pump arm/lever in the right index hole?

Plus, Why has the kick down lever been removed?

Dennis

Oh....Please Don't Ask Me Any Tough Questions As:
"I'm Saving Up MY Memory For When I Develop Alzheimer's"






78 F-150 429CJ C6 ,Silver w/Explorer Pkge
641/2 Mustang,Pre-World's Fair Car #8092
64 Fairlane S/C waiting for a 390-4spd.
68-Mustang.Sunlit Gold 80,000 miles

 

You know, I don't really know if it is in the right hole or not. I guess that's the next thing to check. We did hook up the downshift lever. It was off because the previous owner had installed a rochester quadrajet and gee, nothing fit. I hate when guys mix parts between gms and fords and dodges. I'll check into the accelerator pump linkage and reply back.
Have you ever heard of a float absorbing heavy metals from fuel and therefore sitting too low in the float bowl? Sounds strange to me. And also I've been told that these carbs have no direct linkage between the primaries and secondaries. Is it just a spring linkage? Is there any way for the secondaries to remain open under no throttle?

 

The floats can naturally decide to have pin holes in them and start to submerge ,They can get gummed up from gasoline additives(as I was told).

Doesn't your carb have Vacuum secondaries ?


Dennis

Oh....Please Don't Ask Me Any Tough Questions As:
"I'm Saving Up MY Memory For When I Develop Alzheimer's"






78 F-150 429CJ C6 ,Silver w/Explorer Pkge
641/2 Mustang,Pre-World's Fair Car #8092
64 Fairlane S/C waiting for a 390-4spd.
68-Mustang.Sunlit Gold 80,000 miles