200 carbs

[FastRonald]

8) Okay.....what year did Ford / Holly STOP putting adjustable mixture screws in one barrel carbs? The Holley on my oldest Son's car has the sealed mixture and I hate it. We could use just a bit less mixture and can't do a thing. I did install a smaller jet in the carb at the rebuild. Suggestions? Maybe a a late 70's 200/250 carb?

 

[Anonymous]

Hi, Fast-
what kind of car is it?
The late '70s 3.3L version of the 200 used mostly the 1.75" throat Holley 1946 carbs. If you have an intake hole of 1.625" like the '60s Mustangs, then you'll have problems unless you change the head, too. Check that intake hole size.

The 1946 is a very advanced carb, with 7volt electric choke, hot idle compensation, high-vacuum power valve (non-adjustable, though) and a curve suited for engines with EGR circuits. If you plunck one of these on a non-EGR engine, it will run a little rich in the low midrange (1000-1500 RPM), which will give a noticeable increase in that "launch" into traffic from a standing stop. You may find that you have to add about 2 degrees static spark advance to your usual setting to compensate for the richness and keep your plugs clean - or go to the next step hotter plug.

The idle screw on the 1946 should be set as follows: on a fully-warmed up engine, adjsut speed to about 600 RPM. Then adjust the mixture screw for fastest idle at that setting: if it goes over 750 RPM during this part, slow it down again. Repeat until the fastest idle is obtained, then turn it IN until the speed drops 25-50 RPM from the highest point. Then adjust the final speed with the throttle stop (idle) screw to 650 RPM (manual trans) or 750 RPM (auto trans) in neutral.

One last item: the electric choke on the 1946 works like this: below 50 degrees temperature (at the choke body), the electric heater is 'open' and will not warm up. Above 50 degrees it starts accepting current and heating up, opening itself. Because of this, you MUST supply warmed-up air (like from the exhaust header, thru a steel wool filter, or a metal tube, wrapped several turns around the exhaust manifold) into the port on the side of the choke housing. If you don't the choke will never open. Of course, you can convert it to manual with a kit from Checker, which is the most gas-saving method, anyway. The 7 volt choke's wire comes from the type of alternators that have a 'center tap' on the back just for this purpose. The Fairmonts and Zephyrs in the junkyards ALL have these trouble-free alternators, which work better than the older Mustang units, anyway. I think they'll bolt right on, and they have dual-belt pulleys as a bonus.

I don't know much about the Carter or Motorcraft 1bbl carbs for these engines, just this Holley.

 

[JT81stang]

FastRonald:

Holley never stopped putting adjustable mixture screws on thier carb's.
Yours just has a cap on it.
Later model 1 bbls. were set from the factory & then a cap put over the mixture screw to prevent tampering.
To get the cap off, just drill a small hole in the middle of it and screw in a sheet metal screw and then pull the cap off with a pair of vise-grips on the screw.
The mixture screw will have an allen head on it.

John

 

[FastRonald]

8) Thanks John.......ours is sealed up tight. I may try that little trick to gain that little extra mixture adjustment. The car has a 1945 / 1946 Holley
and is the original carb on my odldest Son's 200 1981 Granada GLX Fox body car.

 

[FastRonald]

8) I should confess....my Son's and I are giving thoughts to doing a S.O.H.C. Mod motor swap on down the road. IF and when we get the donor car and parts to pull it off. In the meantime, the good old reliable 200 still has a job.