Ford Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
New member here fellas ----I rebuilt a 1965 Mercury 390 to stock specs, with the exception of the oil pump and the pistons( .020 over ) I had a Autolite 4100 carb that came with the car which run the car real nice BUT I can not keep the floats from sticking . I finally got fed up with the flooding and put a new Holley 4160 600 CFM carb on and I can't quite seem to get the idle right, seems to miss every so slighlty or the motor just plan idles rough ( I am used to small blocks this is my 1st FE rebuild) I have checked with propane for vacuum leaks and found none ( Belive me this is a full size Mercury and the whole car runs on Vacuum- Heater control, vents wipers etc)
The other iritating isuue is a slight surging when at cruising speed , the other people in the car say they can't feel or hear it but I can.

Any comment or suggestions would be greatly appreciated
Is the CFM on the Holley Okay for this car?
 

·
63-1/2 Galaxie
Joined
·
323 Posts
Hi, I have rebuilt a couple of these Autolite 4100 carbs, as my 63-1/2 Galaxie 390 has one on it. Kits are still available. If your carb is flooding and you say the floats are sticking, they must be not closing the needle valve that hangs on the end of the float tab. Did you install a new kit? It seems they might be binding somewhere on the shaft they sit on, is the small tension spring installed correctly? Also check to see if the floats themselves have any pinholes in them. What float setting are you using, there is a dry and a wet float setting, you have to use one or the other. Check the ends of the needle valve (the rubber tip) and make sure its not rotted. Another problem you might have is the primary jet size, are they too big? I have experienced some surging also at highway speeds (50-60 mph) but I have size 50 jets in the primary and am presently trying to find size 52 which according to the shop manual is what I should have and this would likely correct the problem of surging. Overall I prefer the Autolite 4100 carb, it was on my car when I first bought it 18 years ago and never basically touched the carb until about three years ago and installed a rebuild kit. The Holley is a good carb too and was also used by Ford on many of their cars. The best thing I like about the Holley is that you can set the float levels from outside the fuel bowl. I had one on my old 76 truck and that carb had a flaw from the factory, had to shim up the throttle shaft when it was new account of a poor fit. I also just rebuilt a 4100 carb last year for a 66 Thunderbird and the guy has had no problems with it. Might be good idea to check your vacuum on the car too, a vacuum reading of 18 is pretty much standard and the needle on the vacuum gauge should not quiver or vibrate, it should be steady, any reading lower you have a vacuum leak. If you want info on the carb let me know as those 4100's are pretty much the same through the early to mid sixties.
 

·
Registered
Joined
·
2 Posts
Hmm. What makes the needle quiver? I put my 390 back together and get good vacuum but the needle won’t stand still.
 

·
Super Moderator
Joined
·
8,465 Posts
This thread is from 2005, I suggest you start a new thread with a little information about your setup.
 
1 - 4 of 4 Posts
Top