Reading my spark plugs; Fuel? Oil? Valve Seals? Carb leaking?

[Davea Lux]

First, I would give the fast idle cam and the choke butterfly a shot of spray lubricant to see if that improves function. The throttle butterfly should move freely, give it a shot of lubricant also. Next check to see if the fast idle cam drops completely when the engine is warmed up. Check the heat riser to be sure it moves freely, the automatic choke will not function properly without a working heat riser. If you are still having problems, try unhooking the linkage from the choke dash pot. Does the choke butterfly move freely? Sometimes the spring inside the choke dash pot in the manifold goes south and binds up. if so, you will need a new unit. If you replaced the base carb gasket recently, it could be the wrong one and be binding on the car butterfly.

Dave

 

[GG-1]

First, I would give the fast idle cam and the choke butterfly a shot of spray lubricant to see if that improves function. The throttle butterfly should move freely, give it a shot of lubricant also. Next check to see if the fast idle cam drops completely when the engine is warmed up. Check the heat riser to be sure it moves freely, the automatic choke will not function properly without a working heat riser. If you are still having problems, try unhooking the linkage from the choke dash pot. Does the choke butterfly move freely? Sometimes the spring inside the choke dash pot in the manifold goes south and binds up. if so, you will need a new unit. If you replaced the base carb gasket recently, it could be the wrong one and be binding on the car butterfly.

Dave

Hi Dave,
Ok, but I doubt that anything needs lubrication.. it's all very clean, and doesn't feel like that kind of binding.
It can't be the heat riser either, as I've had that tied open for the last 2 years/1000 miles with good results, and the divorced choke coil in the manifold heats up and functions as it should. I never put car into gear until the butterfly is fully open. I will check the fast idle cam upon warm up next time, to see if drops all the way.. but the choke does open all the way once the car is warmed up.. it just doesn't stay open all the way once throttle is moved. Also something to note, it does not matter how far the throttle is opened, or how fast.. it still does not close completely, and still moves the choke plate towards closed. The thing is, this happened immediately after I tightened down the carb and manifold. Removed carb and divorced choke spring and rod are working as they should. Butterfly moves freely. Throttle shaft moves freely too. Carb gasket is the correct oem for this carb, and like I said, no problems for 1000 miles.. until I tightened it down a week ago.
Unless there is suddenly a problem with the throttle cable from the pedal.. I could disconnect the cable and see if sticking persists.

 

[1970cat]

just because, have you tried to unbolt the carb and re-seat it?

 

[GG-1]

just because, have you tried to unbolt the carb and re-seat it?

Good suggestion.. it actually makes the most sense.. earlier tonight I did just that, being careful not to over torque bolts, tightened just enough to prevent vacuum leaks. I even used a brand new oem gasket I had from Mikes Carburetor(I have a few extras in a box). Drove the car several miles, same exact issues persist.
I ran out of time and had to shut it down for the night(to catch the last train back to Grand Central). This is frustrating.. what the hell am I missing? Maybe I need to reseat it a few times to get it right? Also, the temperature has dropped dramatically since this began happening...

Could the carb body have warped permantly from tightening that one time? To have affected the throttle rod, linkage? I did not torque down on it that hard. Ugh.

 

[1970cat]

Good suggestion.. it actually makes the most sense.. earlier tonight I did just that, being careful not to over torque bolts, tightened just enough to prevent vacuum leaks. I even used a brand new oem gasket I had from Mikes Carburetor(I have a few extras in a box). Drove the car several miles, same exact issues persist.
I ran out of time and had to shut it down for the night(to catch the last train back to Grand Central). This is frustrating.. what the hell am I missing? Maybe I need to reseat it a few times to get it right? Also, the temperature has dropped dramatically since this began happening...

Could the carb body have warped permantly from tightening that one time? To have affected the throttle rod, linkage? I did not torque down on it that hard. Ugh.

it shouldn't have warped that badly. i just thought it might have a little twist. are you positive that the base gasket openings are large enough to allow the butterflies to move freely ? i have had it happen before that i had to trim the gasket a bit.

 

[GG-1]

it shouldn't have warped that badly. i just thought it might have a little twist. are you positive that the base gasket openings are large enough to allow the butterflies to move freely ? i have had it happen before that i had to trim the gasket a bit.

Yeah, hopefully it's that and that will be that.. next time I'm with her I'll look at that first and go from there.

 

[GG-1]

Thanks guys, for your thoughts and suggestions.. I'll report back with results

 

[GG-1]

Re-gap and reinstall. Auto-Lites are not my first choice for plugs as the heat range is not quite right. See if you can locate a set of Champion J11Y plugs as they are correct for most Mopars. Some are for sale and reasonable on E-Bay.

Dave

I just read that the hi-perf/police B/RB Chrysler Corp. 350, 361, 383, 400, 413, 426 Street WEDGE, and 440s usually had J-10Y Champions as their stock spark plugs. Normal 4bbl engines could range a bit warmer into J-11 or J-12YY territory, with the 383 2bbls being Champion J-14Ys.
My engine is a factory 383 Commando High Performance with a four barrel. So wouldn't it be optimal to go with the slightly cooler factory plug specs of J-10-Y?

 

[cantflip]

I just read that the hi-perf/police B/RB Chrysler Corp. 350, 361, 383, 400, 413, 426 Street WEDGE, and 440s usually had J-10Y Champions as their stock spark plugs. Normal 4bbl engines could range a bit warmer into J-11 or J-12YY territory, with the 383 2bbls being Champion J-14Ys.
My engine is a factory 383 Commando High Performance with a four barrel. So wouldn't it be optimal to go with the slightly hotter factory plug specs of J-10-Y?

Just catching up with this thread...

FIRST and MOST IMPORTANT... put in for the July vacation time and plan to join us at Carlisle...

Second, the plugs looked fine... without other drivability symptoms, I wouldn't worry too hard. I know others who would disagree, but since Champion is no longer Champion... just stick with appropriate, cheap, copper plugs and only change things if you get symptoms like fouled plugs or spark rattle... although you could get some minor hesitation from an incorrect heat range too, you're more likely to cause trouble than fix trouble getting creative.

I have trouble getting a set of undamaged plugs from the parts store, let alone an online seller. If a good deal pops up, grab a set to find out how you feel.

The advice to spray a little lube on the linkage was good, WD40 or similar light penetrating oil sprayed on all linkages is recommended. A little light reading in your FSM may help you understand the carburetor and choke better... always a plus when trying to diagnose. Give detailed pictures of the carb, linkage and choke to help with whatever problems persist.

 

[GG-1]

So, I've at least solved and resolved the choke issue. It was malfunctioning because of the rod(pictured) being connected improperly(lever was in wrong position when rod was connected).. took me a while but through comparing it to other properly working Carter AFBs I figured it out.
As for the throttle not returning all the way, I'm still miffed.
The distance it needs to travel to be completely closed is paper thin! Ugh. I can open it a millimeter or an inch, slowly or quickly and it still won't return that teeny tiny bit, sticking at about 100 rpms above my normal set idle speed. At least I know now it is consistent. I'll try lubricating the throttle shaft and other associated linkages with wd40, although I was always advised not to, as that would attract more dirt and crud quickly causing further binding issues. I also removed the throttle cable from the carb that comes from the accelerator pedal and the problem persists.
I really don't think the culprit is dirt or rust. But it did happen suddenly and isn't "working itself out" by driving her.

 

[GG-1]

Just catching up with this thread...

FIRST and MOST IMPORTANT... put in for the July vacation time and plan to join us at Carlisle...

Second, the plugs looked fine... without other drivability symptoms, I wouldn't worry too hard. I know others who would disagree, but since Champion is no longer Champion... just stick with appropriate, cheap, copper plugs and only change things if you get symptoms like fouled plugs or spark rattle... although you could get some minor hesitation from an incorrect heat range too, you're more likely to cause trouble than fix trouble getting creative.

I have trouble getting a set of undamaged plugs from the parts store, let alone an online seller. If a good deal pops up, grab a set to find out how you feel.

The advice to spray a little lube on the linkage was good, WD40 or similar light penetrating oil sprayed on all linkages is recommended. A little light reading in your FSM may help you understand the carburetor and choke better... always a plus when trying to diagnose. Give detailed pictures of the carb, linkage and choke to help with whatever problems persist.

Thank you, I am learning more and more each time I've got an issue, as I'm very hands-on with just about everything. I figured out the choke issue and that now functions perfectly after a minor but critical re-adjustment.
I've just gotta take a very close look at everything involving the throttle shaft, as I now know it's not the cable causing it to stick open by a hair.
As for Carlisle, I'd love to go and see it all, and meet some of the FCBO members . I hope to be there in 2019.

 

[GG-1]

 

[rags]

worn throttle shaft or bore can cause throttle bind with engine running. vacuum pulls the shaft off center causing misalignment of the throttle blades in their bores.

 

[GG-1]

worn throttle shaft or bore can cause throttle bind with engine running. vacuum pulls the shaft off center causing misalignment of the throttle blades in their bores.

Entire car has only 15k miles.
Entire carb was rebuilt recently, has less than 900 miles on it, and the throttle shaft bushings were also redone at that time(btw, not done because of a bushing problem, just for good measure).


As mentioned before, the throttle has always returned/closed fully until now, immediately after re-tightening the bolts at the base of carb to the manifold. It hangs open a MICROSCOPIC distance, which can be pushed closed by hand when applying some pressure to the throttle lever.. you don't even feel movement it's so slight, but when pushed closed the rpms drop by over 100 to normal idle speed, and it STAYS closed until the throttle is moved open again in any way, either very slightly, slowly, quickly or greatly.

 

[Ripinator]

Entire carb was rebuilt recently, has less than 900 miles on it, and the throttle shaft bushings were also redone at that time(btw, not done because of a bushing problem, just for good measure).

As mentioned before, the throttle has returned/closed fully until now, immediately after re-tightening the bolts at the base of carb to the manifold. It hangs open a MICROSCOPIC distance, which can be pushed closed by hand when applying a fair amount of pressure to the throttle lever.. you don't even feel movement it's so slight, but when pushed closed the rpms drop by over 100 to normal idle speed, and it STAYS closed until the throttle is moved open again in any way, either very slightly, slowly, quickly or greatly.

After reading all the suggestions and your description of the problem with the throttle hanging up, I think you may want to check your vacuum operated choke pull-off. If it is not operating correctly, it could cause the throttle to hang a bit.

 

[GG-1]

After reading all the suggestions and your description of the problem with the throttle hanging up, I think you may want to check your vacuum operated choke pull-off. If it is not operating correctly, it could cause the throttle to hang a bit.

Ok, I'll read up on why and how that may cause this problem. I do know that upon start up, I push the gas pedal down once, the choke closes shut, and on the first turn of the key she starts right up.. and the choke butterfly blows open partially like it should.. and eventually as the engine warms up, the choke plate opens all the way.. this takes about 10-15 minutes, which seems like a long time.. I also have my heat riser wired open until I get a new thermostatic spring, so that may retard choke opening due to lack of heat to the manifold and also divorced choke spring. Still, the throttle hanging open even that little bit while driving, and during braking is disconcerting. Maybe the accelerator pump is sticking at the end of its travel back up?
I'm
Big thanks to all contributing with experience, expertise and some common sense.

 

[GG-1]

First, I would give the fast idle cam and the choke butterfly a shot of spray lubricant to see if that improves function. The throttle butterfly should move freely, give it a shot of lubricant also. Next check to see if the fast idle cam drops completely when the engine is warmed up. Check the heat riser to be sure it moves freely, the automatic choke will not function properly without a working heat riser. If you are still having problems, try unhooking the linkage from the choke dash pot. Does the choke butterfly move freely? Sometimes the spring inside the choke dash pot in the manifold goes south and binds up. if so, you will need a new unit. If you replaced the base carb gasket recently, it could be the wrong one and be binding on the car butterfly.

Dave

Hi Dave,
So if the fast idle cam does not drop completely once warmed up, then what? If it barely engages once completely warm, how do I adjust it so it drops that extra hair? It moves freely on it's own. Maybe I've moved something out of adjustment. Thanks.

 

[Davea Lux]

Hi Dave,
So if the fast idle cam does not drop completely once warmed up, then what? If it barely engages once completely warm, how do I adjust it so it drops that extra hair? It moves freely on it's own. Maybe I've moved something out of adjustment. Thanks.

Bend the linkage rod carefully until the cam drops all the way down, once it is all the way down, there is an adjusting screw to set the idle speed at the various positions on the cam.

Dave

 

[GG-1]

Bend the linkage rod carefully until the cam drops all the way down, once it is all the way down, there is an adjusting screw to set the idle speed at the various positions on the cam.

Dave

My fast idle speed is good upon start up. I clearly should bend the rod while engine is up to temp.. but where and how I don't know...
Do I need to touch the idle screw or fast idle screw at all once I set the cam free?

 

[Davea Lux]

View attachment 228062 View attachment 228063
My fast idle speed is good upon start up. I clearly should bend the rod while engine is up to temp.. but where and how I don't know...
Do I need to touch the idle screw or fast idle screw at all once I set the cam free?

Try backing off the fast idle screw about 1/2 turn before you bend anything to see if that closes the throttle plate. The rod you have featured is the correct one to bend if that becomes necessary.

Dave