camocreek

Hey all, quick question, how do I know if the carb on my 70 Mustang Mach 1 is electric or manual choke? It's a Holley 600cfm LIST-9834 which I've found to be a model 4160.

Thanks!

lClutchl

Manual choke will have a cable running to the opposite side of the carb as the throttle linkage.

An electric choke will have two wires on that side.


IE... this is a electric choke 4160 carb...



Notice the round black object with the two wires coming out of it? That's the electric choke. A manual would have a cable and linkage in it's place.



(The yellow wires were for test only... I swear!)

camocreek

Ok thanks!
Next question, how tough is it to rebuild a carb? Would this be easier than buying a new/used one? The reason I ask is because I get quite a bit of hesitation when I give the car some pedal, like it's not getting enough gas, then all the sudden it'll kick in and take off. The previous owner ran it with rust in the tank, even though he had an inline fuel filter, I still suspect some of that got through and into the carb. I put in a new tank and the gas has been clean running through the filter, so I'm guessing the carb either needs rebuilding or replacing. Any suggestions?

Thanks again.

lClutchl

Sounds like your accellerator pump needs adjusting. Personally, I would rebuild the carb you have. It's a lot cheaper, and you will learn a lot, and your car will gain gobs of performance from the tuning.

4160 rebuild and adjustment guide

Holley 4160 adjustment guide

Frist thing... get yourself a GENUINE HOLLEY rebuild kit. The knock offs are not as high quality as the holley brand stuff. Plus, your not saving that much anyways.

Then READ the documents above TWICE! After you have read them, you should have no problem with a first rebuild.

There are tons of books out there on how to adjust and tune your Holley, you can take it as far as you want. Personally, I think it's kind of fun to tweak the carb!

Good luck!

lClutchl

Oh, I forgot to mention, A new Holley will require all the same tuning you would need to do on your rebuilt carb. (since the 4160 is set up from the factory to work on a variety of engines, it's nowhere near tuned for your specific setup)

camocreek

Thanks for all the information, I'm going to go pick up a rebuild kit tomorrow.

speedjunkie

Don’t forget to blow out all the ports and jets with compressed air. Small particles of rust will go thru the filter and lodge in the carb.

68FastbackGT

I just rebuild my Holly this weekend. It ran OK before, but after the rebuild I noticed a big difference in throttle response. Well worth the effort. It took 2 or 3 hours, but I was taking my time. Definitely use compressed air to clean out every orifice. The only special tool need for the job (other that the compressor) is a hour glass tip shaped screwdriver to remove the secondary fuel circuit.
I think I used a generic rebuild kit. I will know better next time. I need to rebuild the holly on my mother-in-laws 83 mastercraft next.

I have a few questions of my own to add to this thread.
Where is a good place to get a GENUINE HOLLEY rebuild kit?
How do you know if the vacuumed actuated secondary is working?

Thanks in advance.

lClutchl

I get the genuine stuff from performance shops. Ramchargers is local to me, but if your out in the boonies, Summit is a great mail order.


Vacuum secondaries...

They only open up when the engine is under load. They will NEVER open by just "winging" the throttle. The best way to see if they are working is to disconnect the secondary linkage, drive the car, and note the performance drop. If you don't notice any drop in performance, you have a problem.

68FastbackGT

Thanks IClutchI
After reading in the manual that the secondary would not work if it had a vacuum leak, I became worried. The carb is around 20 years old and I have never replaced the diaphragm in the secondary actuator. I became more worried when the secondary did not open when I floored the throttle. As you pointed out, this is a erroneous test. I will disconnect the manual linkage to the secondary and test it as you prescribed.

My mustang and me thank you.