Just picked up my 68 Fury III a couple of days ago. It has a 318 with the 2 bbls. Love the car, but it needs some things. The first thing is the cold starting. When I try to start it cold it won't idle after I've let it warm up after choking. I have to keep the revs up to keep it running especially when I put it into gear. It starts idling really low like its going to die and the headlights dim pretty bad. Its been a while since I've owned a carbureted car and my last one wasn't as old as this one (82 Toyota pick-up). I'm not sure if its the timing or the carb or the choke... or all three. Thanks in advance.
Joined: Sat Jun 07 2008, 12:59AM
Location: Fort Lewis, Washington
Posts: 394
Ok first, check to make sure your choke is in fact working. It should have a mechanical choke, so when the engine is cold depress the throttle about halfway and let it go, the choke plate should be closed and the idle speed should be on the "cold idle cam." I assume the choke is working correctly. I would be willing to bet that your "hot idle" is out of adjustment. If memory serves on those Stromberg/Carter 2bbl carbs the idle screw is the same for both hot and cold, the cold idle is just run off of a cam connected to the choke coil. When the carb is off of the cold idle circuit you will need to adjust the hot idle screw to the correct RPM. It should only take a few minutes of running to get the carb off of the cold idle setting. For a stock 2bbl 318 (correct me if im wrong here) I think the cold idle should be around 1100-1200 RPM and the hot idle should be around 700-800....hope this helps
Joined: Fri Mar 13 2009, 11:21AM
Location: San Marcos, CA
Posts: 713
To be sure what you are referring to: does the motor start up and idle OK until a couple minutes, then run bad until it gets all the way up to temp and then runs OK? or does it have a problem idling when warm? If it is the first one, check the choke pull off, it should open the choke a little, as soon as the motor starts. If the choke doesn't open ~3/16 to 1/4" the choke pull off isn't working. The exhaust cross over could also be plugged making the choke stay "on" for too long too. My $.02
Joined: Sat Jun 07 2008, 12:59AM
Location: Fort Lewis, Washington
Posts: 394
Also, and this just came to me like a punch to the head, check to make sure you don't have any vacuum leaks as they will cause erratic idling problems too.
I would be willing to bet your exhaust crossover is plugged, especially if it has never seen the light of day before.
The car has a hard time staying running while choking and what I think should be "warmed up". I have been looking at the choke and it seems to work right. If I put the pedal to the floor to set it, it sets the choke but I'm not sure if it goes as far as it should. Should the choke set all the way everytime I put the pedal to the floor before starting it? Thanks for your help guys.
Joined: Fri Mar 13 2009, 11:21AM
Location: San Marcos, CA
Posts: 713
Normally the choke goes fully closed after pushing down on the throttle. I've had best luck with it with it adjusted with just a little force holding it closed. Pushing on the throttle to "set" the choke is necessary to get the fast idle screw over the bump on the fast idle cam. When the motor starts, the choke pull off will open the choke to a position that gives the motor enough choke to keep it running but not too much that will flood the motor. The exhaust crossover feeds hot exhaust gases under the intake manifold to make the choke stove heat up and open the choke. The heat riser on the pass side makes the exhaust go across the intake manifold. If the exhaust crossover is plugged the choke won't open as fast as it should. The fast idle and curb idle speed adjust are separate speed adjustments that both need to be set. if you can get a factory service manual that will tell you how to adjust all the settings and make the motor start and run like it should. I hope this helps.
Joined: Sat Jun 07 2008, 12:59AM
Location: Fort Lewis, Washington
Posts: 394
Cahir Rua wrote ... The car has a hard time staying running while choking and what I think should be "warmed up". I have been looking at the choke and it seems to work right. If I put the pedal to the floor to set it, it sets the choke but I'm not sure if it goes as far as it should. Should the choke set all the way everytime I put the pedal to the floor before starting it? Thanks for your help guys.
When the engine is cold, yes the choke should close when you push the pedal, but after the engine has been running for a few minutes (warmed up) it wont close again due to the thermostatic coil located in the choke well on the intake manifold. When you say hard time staying running do you mean the idle just goes down so low it wants to die and you have to use your foot on the gas to keep it running, or is it surging up and down and sputtering? The two screws located on the throttle lever on the driver's side of the carb are the curb idle and fast idle screws. Turning them clockwise will raise the idle speed, counterclockwise will lower it. The fast idle screw needs to rest against the fast idle cam which is connected to the choke (choke open the cam rotates out of the way to allow the car to idle down). The curb idle screw is adjusted only after you make sure you are off of your cold idle circuit. Often times the throttle return spring puts enough pressure on the cold idle screw/cam to keep the choke closed until you rev the engine a little bit. I would have someone start the car while you are looking under the hood, screwdriver in hand, ready to adjust those idle screws. If they have to use their foot a little bit to keep the idle up so she doesnt die, that's ok. Set those two adjustments and you should be ok.
Joined: Fri Oct 07 2005, 12:03PM
Location: Central Ky.
Posts: 1575
A lot of of times on cars this old the choke Pull-off diaphragm is shot & thus doesn't work & you'll get an over-rich condition during the warm-up cycle.
Just ran into that on a customers car.
Also, the thermostatic coil down in the choke well is adjustable. If you take the arm loose from the carb & remove the 2 bolts ( 7 / 16th ) holding it to the intake you can adjust it. Loosen the nut & you can turn it to move the arm higher if needed to make the choke blade tighter or the reverse if it's too rich.
I checked the exhaust crossover hose and it was clear. The choke maybe just slightly out of adjustment. I'm thinking it might be something bigger like the carburetor and or timing. I bought a carb kit to rebuild the carb and I've got a timing light. So, we will see if those two things work. Speaking of timing, on an auto I read that the timing is something like 2 1/2 BTC... or something like that. My question is, is that the mark to the right of 0* TDC? Mine is hard to make out. And do I just rotate the distributor until it lines up with that mark? Like I said its been a while for me. Thanks.
Joined: Sat Jun 07 2008, 12:59AM
Location: Fort Lewis, Washington
Posts: 394
The marks to the right of the 0 are retarded, the marks to the left are advanced. Yes with the engine running and warmed up, pull the hose from your vacuum advance and plug it, loosen the distributor hold down bolt and SLOWLY rotate the whole distributor while pointing your timing light at the crank damper. You can put some chalk or baby powder in the TDC groove on the damper to make it easier to see. Rotating the distributor clockwise will advance the timing, counterclockwise will retard it. Once you get the timing to 2 1/2 - 3 degrees advanced tighten down the distributor hold down bolt, reconnect the vacuum advance, and you will probably have to reset the curb idle again as advancing the timing will raise your idle speed. I have no idea what the factory initial timing is supposed to be set at for your car, so 2 1/2 is just a guess based on what you said.
