At least it runs like one...... Ok, I have an 8BA in my '37 truck. I run it about 5 or six times a year. This morning I fired it up and it wouldn't idle, and sounded rough. I jacked up the idle, took about 5 turns. I statred shorting out plug wires and found the two outer ones on the pass side (1 and 4) were not functioning, on the drivers side, the two middle ones (6 and 7) were dead as well. Seemed odd. The plugs are almost new, so I swapped them around with the 'good' ones. No diffrence. Tried different wires known to be good. Checked timing, firing order, everything I could think of. It runs exactly the same with the 4 wires described completely off the truck. Compression? 75-80 on all cyls, just checked. I notice these 4 cyls are all fed by one side of the carb. I didn't have an air cleaner on it for a while and we have wasps and yellowjackets, so I pulled the carb thinking somehow, even with throttle plates closed, something built a nest or I sucked one in to that port on startup. Clean as a whistle in there.... Now I'm thinking does one side of the carb (ford model EC) function independently from the other? That's all I can come up with. When I pull the plug wires off the 'dead' cyls, they arc to the head (or my hands) just as ferrociously as the active ones. Any ideas? I was supposed to be unloading a huge stack of lumber today, but this has got the better of me, and I can't stay away from it. Thanks in advance.

 

I wish I could help Gibb. Sounds like more than one thing wrong.
Also reminds me of the V4 Wisconsin. What a cool industrial engine
they are. They used to be a butt load of them around running conveyers
and shakers at the rock pits. I just never see them any more.

 

My bet is that one of the intake valves stuck open. This is not the correct way, but I had a 34 V8 that did that. I could see which one it was through the spark plug hole, so I started it up with the plug out and tapped lightly on the valve head. Worked fine, but you do it at your own risk

 

Yes, once you get past the fuel bowl, it is like two independent carburetors. I'd bet the idle circuit or main jet on one side is plugged, but you might as well just clean everything. They are very simple carbs, just work over a workbench so nothing takes off on you. As long as you disassemble it carefully, it usually isn't necessary to replace gaskets.

If you take out the idle mixture screws, and put the nozzle from a can of carb cleaner in each hole, you should see cleaner squirting out of a hole just above the throttle plate, and also from one of the venturi nozzles.

 

The two out side cyl on one side and the two inside cyl on the other side use the same carb plenum - If you get past the carb as Ross said in the above post and everything is OK the check the airflow - Pull the coil wire crank it over and see if you have any back flow thru the carb if you do you have a stuck intake valve if not pull a plug and see if you are getting good flow thru plug hole if not you have an obstruction in the plenum - A mouse could have built a house

 

Are we talking about this truck? I love her prolly even more than Abby.

When you die can I have it? Hey guys I asked here first.

 

That's it! And thanks all you guys for the hints. I doubt 4 intake valves are stuck.... Will I find that all the cyls on one branch of the plenum are dead with one stuck valve? I will go through the carb tomorrow morning after my wife leaves for work and before my employee shows up. The gas smell should have dissapated from the kitchen table by then. And now I'm thinking that there can be no suction through the plenum for any cyls there, as the stuck one is like a giant vacuum leak? .... hmmmmmm I have dealt with ba lot of stuck valves in the past, at least there's no push rods to bend!

 

One stuck open INTAKE valve will lean out four cylinders to the point they will not fire. It will act the same as if one side of the carb is plugged

 

I think the carb is more likely than valves, compression is the same on all cylinders.

 

In the last hour I re-checked the compression in the 4 suspect cyls. 80-90 in the four non firing ones. Then I took the carb apart on some cardboard on the flatbed and pulled the plugs in the floatbowl and removed the jets in there. Are these the main jets? Then I cleaned them out with carb cleaner and air. I didn't blow out the passages behind them. Then the same with the idle adjustment screws. Didn't have a red straw for the carb cleaner so was hard to tell if it came out in both places, but I could see the top hole spraying. Nothing definitive. Put all back together and it started right up and ran like it did before. Same 4 cyls nothing. I do however notice that it revs up real nice and seems to have normal power running the hills on my place. It's really hard to tell at a FAST idle like 1500 rpms if the speed dips with plugs shorted. . This leads me to think idle circuit. One other thing I noticed, the vac wiper port pulls from this side, and mine is plugged with a hose and a bolt, as I don't need wipers, so I thought maybe vacuum leak at my hose plug. I pulled the hose off at idle expecting it to die, but it ran better, or at least the idle speed went up considerably... ?? I might need to do a major on the carb, but did 5 years (100 miles) ago. Maybe the ethanol gas doing its thing in storage. ??

 

Yes, those are the main jets. It does sound like it's just the slow speed system that's plugged. You really need to take it all the way apart to clean all the passages.

 

Now that we seem to have narrowed it down to the carb idle circuit, I will get into it properly next weekend. For tomorrow I'm gonna load the bed with wood so I can stick it back in the shed and both the wood and the truck stay dry. I only need 4 clyinders to get it back in the shed. Thanks so much for all the advice. I will update next week after I rebuild the carb.

 

I've had this same thing happen with my Fords and some belonging to others. It's nearly always a clogged passage in the idle or low speed circuit of the carburetor. A trick that I've seen old timers do to cure it (works sometimes) is to cross a couple of plug wires and start the engine in order to cause it to 'pop back' in the carburetor. It's probably safer to do this with the air cleaner in place. Often the pressure caused by popping back will dislodge the obstruction and it will go on through the passage. I usually do this with the mixture screws backed way out, or sometimes even removed from the carb. If you can get it to pop back a couple times when the throttle valves are only partially open, more of the resulting pressure will be forced back into the low speed circuit and is more likely to clear the blockage. I've got this to work on a lot of newer Fords with the 2100 carbs also. It doesn't seem to hurt anything to try this, and can save you from having to tear down the carburetor if it does work. If it doesn't help then disassemble the carb and thoroughly clean, paying special attention to the low speed and idle passages. Blow air through them and make sure it comes out the other side, or you can use a bright light to try seeing through them. You can use a piece of wiper hose and apply air pressure with your mouth to test to see if passages are open, etc. I know well that "V4 sound" at part throttle - nearly always means a clogged low speed circuit. Good luck with it. That's a beautiful old truck!

 

It can also take out the power valve, unfortunately.

 

As much as I love old shade tree mechanic techniques, maybe I'll go the long route jic, and do it over the weekend. Easy carb for sure and a 1/2" wrench takes care of everything in the removal. (good old days)..... I already did the 'rev it up and put the palm of your hand over the carb' thing to try to pull the junk through. Always wondered how much suction the hand can take.......