Need some help my flathead only runs on four cylinders when idleing,cylinders 1,4,6 and 7 do not run can pull plug wires off and there is no change seems to have plenty of spark. Funny thing is every other cylinder in the firing order is not running,have 125lbs compression in every cylinder, The other thing I noticed is 1,4,6,7 run off of one barrle of the carb and 2,3,6,8 run off the other. Checked the timming seems ok, starts right up as soon as you give it some gas it comes alive and runs on all eight any suggestion. I do have an electric fuel pump and running 2lbs with a regulator. I took the carb off last night and will take it apart to see if I find anything kind of running out of things to look for. Thanks
You just answered your own question. If the half of the motor that does not run is fed by one barrel of the caruretor, there is no fuel passing that side.
Now..."flathead" and "carburetor" do not tell us much...there are numerous variants of each, even dealing with common stock combinations. If Ford/Holley 2 barrel...idle fuel first goes through main jet (does it run on all 8 at higher RPM??, then through idle jet tube (vertical brass piece with screwhead in front of nozzle bar), across nozzle bar (while looking at that clean out the two tiny air bleeds near front of each), down passages through bowl casting and throttle base to apertures. Remove idle adjust screw to get into this area, clear out idle feed hole and off-idle holes above it...and of course investigate everything for crud waiting to pluggit again.
Ok I am just about ready to pull my hair out,I have taken the carb apart several times see no problems,changed the coil,condenser even change the distributor still only runs on four cylinders at idle 2,3,5 and 8. The carb and intake are not stock I have a Holley 2280 with an aluminium intake. I have attached a picture I have read all the post on the loadamatic dizzy but would changeing the carb and intake cause this kind of problems. Thanks
I don't think it is a carb problem, but can you get a longer gas line and turn the carb 180 degrees just to test the idle skipping? Next I'd be thinking vac leak or too much vacuum draw at the base of the carb like a pcv hose?
So what is that carb...'70's mopar? Canadian Merc manifold? If you are using Loadamatic and it is hooked up to either the carb or the manifold, it is actively fighting you, advancing at wrong times and not advancing at all when you get to full throttle. It might very well work better unhooked and left with no advance! It would work much better pounded flat and discarded. Sorry. But anyway...you need to find and study every speck of the idle circuit on the side affected, from bowl to throttle body, including air bleeds. Trouble almost has to be there. The advance problems are probably not serious until car is above idle.
Bruce the carb is a Holley 2280 2GC series p/n R-7664 I purchased it from Johnson's speed shop, 2 barrel from the information that came with it say's it is for a GM truck 307 CI. The numbers I found on the intake are C1CM-9425 I bought it on E-bay, I changed the distributor with another one that I have and there was no change although I did see a much greater degree of advnce between them. I do have a PVC setup on it also which I detached but seemed not to make a differance. I have never ran the engine with a stock carb or Intake I do have a stock setup and have been thinking of changeing it out. Any thought's would be helpful thanks in advance. Keith
Back to basics.Only one thing to check. If you are using Motor Auto Repair Manual 1954 For Fords the firing order is wrong. Mercury is 15486372 This is what i'm running on my 8ba
The load-o-matic distrubuter really needs to be run with a load-o-matic carb. The distributer requires the vacuum signal from the load-o-matic carb to operate correctly. If you are using the distrib without matching carb, where are you getting the vacuum signal to run the load-o-matic distributor? ?? The vacuum signal from the original 94 style carb sends the proper vacuum signal to the distrib and the distrib can properly set timing and advance. Without the correct load-o-matic carbs signal, you are not getting the correct signal and the timing will be effected at every rpm. -You may be able to set initial advance at idle but you will have problems with advance at speed. jmho. I agree with others, Put a Vacuum gauge on it, it will help you find the problem whether carb, spark or valve, ring, plug, or even stuffed muffler. A vacuum gauge is probably one of the most valuable tools a person can own. .
George I have been useing this Diagram but the only problem with it is number one cylinder on my engine is not where this diagram indicates. If you look at the diagram my number one is were they show number six to be,but on the my cap it has a number one on it,and that is were number one is at on my engine. I have seen other diagram that show number one to be where mine is. Will this engine run if it is 180 degree out? Thanks Keith
The diagram is correct Right side 1234, left 5678. But when looking at dist you look straight down. Number 1 on cap left of clip. So number one goes to right side front cylinder,then go around clock wise in the firing order. If 1 is top dead center the rotor will be straight down. I think the wiring is wrong.
If it's only not running right at idle, but ok when the revs are up, then it can't be an incorrectly wired distributor. If it was wired incorrectly, how would it run ok off idle? 99.9% sure it has to be carb related. Could be wrong though! Mart.
George that is the way mine is the rotor is straight down when on TDC. And point to the number one that is on the cap. Thanks Keith D.
If number 1 is straight down, clockwise the next is 5 left front,and go around 15486372. Thats my guess ,if not change intake and look for something wrong.
A flathead only needs four cylinders! A friend of mine has a 59AB that he runs with one head off the engine. People freak out when they see the pistons moving up and down in the bores and the valves opening and closing. It also idles surprisingly smoothly.
It really has to be in idle circuit of carb, one side only, from the backstory. You could use a manual showing the circuits, but if not available just pullitapart, start at the idle hol in base and follow the holes uphill until you reach the carb bowl. Gasket hole missing, dead fruit fly stuch in a passage, dirt in a hole...very likely to be something free and simple. Manifold is Canadian 1951 Merc, bigger passages than most other stock flathead pieces.
Could be a vacuum leak on the carb or manifold side that feeds those cylinders. Maybe a port left open or unknown.
Must be a common flathead problem. This one's only running on four cylinders as well! http://www.youtube.com/watch?v=GDtBGoTiQ90&feature=fvsr
Well what a dumb**** I am!! I rebuilt the stock carb and put the stock intake on and the engine runs great. But you would never beleive what I found during the process ,I had replaced the old bolts on the intake with some studs and S.S. acorn nuts the studs were to long and the acorn nuts were bottomed out. The intake gasket was barely indented and showed signs of having a vacuum leak I checked for a leak but looks like it was leaking towards the inside of the intake so was kind of hidden. Thanks for all the help, planning on leaveing it along and enjoying it for the summer during the winter thinking of going to a deuce setup and changing the dizzy. Thanks Keith D.
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