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StangIN65 09-08-2006 01:19 PM

289 runs rough all of a sudden
 
I have a bit of a mystery. My 1965 289 started acting weird yesterday on the ride home. Yes this is a summertime daily driver. When there is no rain in the forecast. Anyway the old horse started dying out on me. I would have to feather the gas to kep her alive. Today I drove it to work and she kept idling rough. so over lunch I put on a set of points, rotor, cond and cap. and is seems a bit better. But does not idle woth a #*@%. Any ideas?

nick69 09-08-2006 01:36 PM

Sounds like the carb is over fueling, does it smoke a bit when having the problem.
What carb have you got on the motor?

Might be worth cleaning the needle/s and seat/s.

StangIN65 09-08-2006 02:04 PM

289 runs rough all of a sudden
 
I have an autolite 4300
It does not smoke at all. I always have it clean and I know it probably better than any other motor component. I am about to try to get it home on a 13 mile trek. I will give the carb a good goin over tomorrow and let you know what I have or have not figured out by Monday
Cheers

nick69 09-08-2006 02:07 PM

hope the trek goes ok. Also check the fuel filter for debris.

bates_k 09-08-2006 06:43 PM

Is it misfiring...
 
through the carb?? Kinda sounds like a sneeze...
You could have a vacuum leak...

K

trees 09-09-2006 08:55 AM

I would check for a vacuum leak. Could be a hose or even at the base of the carb. There were two different shapes of carb bases and intake bases, referred to as round back and straight back. All will bolt on and rebuild kits include both gaskets. Spraying some carb cleaner or starting cleaner around the back base of the carb will smooth out the idle if that is your problem (or any other place it could be sucking air)

Having said all this, you may have to clean/rebuild your carb. I had the same symptoms on my 68 Bronco 289 and a rebuild solved the problem. We also ran into a round back carb on a square backed intake on my Bud's daughter's 66 Mustang. He milled an aluminum plate and used both gaskets in the kit to solve that problem.

Trees

Trees

StangIN65 09-11-2006 07:06 AM

Update
 
Ok the trek home was ok she only died once on me and started back up. Here is what I have learned. First it is a Motorcraft 4100 not a 4300. Second I discovered that the choke plate became disconnected from the choke spring. I corrected that but alas that was not the problem. I cleaned the PVC valve and blocked off the vacuum advance to the carb and distributor. No change what so ever. Perhaps this may describe the symptom better. The engine tries to idle but at a certain point I have to lightly apply a little gas then it gets back to that same point in the cycle and I have to do it again. She almost wants to idle but not quite. I have removed a few plugs 1, 5 and 3 they have a little carbon on them and I attribute that to the choke being set a little rich. Overall the engine runs strong provided I keep giving her gas. Stop lights are a big problem, one foot on the clutch, one on the brake and one on the gas. Only problem is I only have two feet. :(
Any other Ideas are appreciated.

StangIN65 09-11-2006 07:13 AM

This is the carb except with automatic choke
 
1 Attachment(s)
Here is a tech link I found
http://www.mustangmonthly.com/techar.../photo_01.html

nitro_baller4692 09-11-2006 07:23 AM

whats the fuel pressure like?

StangIN65 09-11-2006 07:31 AM

Fuel Pressure
 
I have not measured it. (don't have the equipment) I started to write that I think that it is ok becuse I get good revs higher up but no idle. But on second thought I am wondering if the pressure was low at idle becuse perhaps the fuel pump was not delivering enough pressure at that one particular point in the cycle of the engine. I would hate to buy a new pump if I didn't have to. I suppose I have a pump on the 302 of another car I am building that only has about 50 mile on it. I suppose for the cost of a gasket I could try it.

StangIN65 09-18-2006 02:11 PM

Latest Update
 
Fuel pressure is good. Tested it by pulling the line and letting her squirt into a can. I had about a pint after 30 seconds or so. Thats the best check I could perform. Got the ol mare up to operating temp and had my dad help keep her going while I sprayed card cleaner around the carb with not change. Then we shut her down and counted the turn all the way in for the two bowls and wrote that down. After a while we got her to idle with about a 1 turn gain on the drivers side, no change on passenger side, a tweak up on the timing and with by setting the idle up.
Now.....
It is better and I can keep it running but it is not smooth as it was before the whole thing happened last week. I am going to yank the carb and swap the gasket as soon as I am sure of the right gasket. Edelbrock Torker II with a Motorcraft 4100.
Any other thoughts, opinions, ideas, hopes or prayers?

65 falcon sprint 09-18-2006 08:14 PM

carb.
 
if there are no vacuum leaks,then its probably the carb,kinda sounds like the accelerator pump in the carb is starting to go bad. after doing everything you have done up to this point,rebuilding the carb. would be my next move.good luck neil

StangIN65 09-19-2006 07:17 AM

Thanks Falcon Sprint
 
I pretty much surmised that would be my next step. I have to track down the right Intake to carb gasket and I have asked Eldebrock for their recommendation. I know the carb need a good cleaning as I can visually see corrosion on the secondary throttle plate. Last spring the only thing I replaced was the primary gasket and plunger. The dog gone thing ran great.

I rode the horse into work today and she seems to surge and stall over a complete cycle. I am sure this is attributed to my current set of adjustments. Finding the rebuild kit is not a problem nor is my capacity to perform the cleaning and refurbish. I just have a haunting in the back of my mind that this is not it. But then donít we all have doubts.

FEDDO 09-19-2006 04:26 PM

carb?
 
Years ago ,and in another life, I had a similiar problem with a 64 fairlane. tried different carbs, points, cond. no help. Carried a friend for a ride, and he said its the dist plate. there is a plate in the dist that the points attach to. I changed that and all of my car problems were solved. had my friend back.if you can't find one I have a spare. hope this helps. jim.

StangIN65 09-20-2006 07:03 AM

Carb?
 
Quote:

Originally Posted by FEDDO
Years ago ,and in another life, I had a similiar problem with a 64 fairlane. tried different carbs, points, cond. no help. Carried a friend for a ride, and he said its the dist plate. there is a plate in the dist that the points attach to. I changed that and all of my car problems were solved. had my friend back.if you can't find one I have a spare. hope this helps. jim.

Jim that is very thoughtful of you and I may take you up on the offer. I have a gut feel that it is not the carb. I have felt it was a "governor" type of feel and since the dist is the governor I have had a suspicion that it could be in the dist. This weekend I plan to do two thing prior to a carb rebuild. (If I have to rebuild it would be during the non-driving season.) One is to remove the plate and inspect it. The second is to replace the carb to intake gasket to allow for a more thorough inspection of the carb and if it is the source of an intermittent vac leak. I will let you know what I find out.
Cheers


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