So I spent the day dinking with it. I took a two foot length of vacuum hose, hooked it to the back of the choke pull-off and sucked on it. It was working just fine, and held a seal, so I guess the diaphragm in that is intact.
As you may recall, yesterday I disconnected the choke, and the choke plate was perpendicular to the top of the block. All lean, no fat, y’know. So, when I tried to crank it this morning, nada. Nothing. Not gonna start with no choke when cold, no way. Starter fluid elicited a good 30 seconds of running, then once that ran out, nothing.
So, last night this guy on one of the Mopar boards I go to for advice offered to send me a choke thermostat! It should be here by the end of next week… I can drive it with the choke on until it’s warm, then disconnect it when it’s running well. No big deal, just put a bag of twist ties in the glove box, etc, right?
Well, that just didn’t sit right with me, so I went and got the can of carb cleaner and a toothbrush and went to work. I sprayed and scrubbed all the linkages for the t-stat, and went ahead and got after the rest of the carb, as well. I drove it about ten miles, came home, lifted the air cleaner can off, and the choke was still closed. I checked to see if the t-stat was articulating at all, and it felt fine- the spring felt springy and the whole assembly seemed in good shape.
Then I remembered what someone at the Mopar board had said…
You will also need to make sure manifold heat valve is working and passage in intake manifold is not blocked with carbon. Manifold area around choke spring should get too hot to touch after only a couple minutes.
I pulled the t-stat off and the little bowl underneath, and underneath was the nastiest ball of crud you have seen in your cotton-pickin’ life. Oh, man, that was some nasty stuff. I started scooping it out with a flathead screwdriver and throwing it away. It was a golfball sized wad of black crud, studded with those Yoohoo-colored globs of water/oil/carbon you see on your dipstick when your head gasket is gone.
Here’s what I think happened: This Dart was a little old lady car. It has 79k original on it, and I bet it was hardly ever driven over 40mph. (It has some “parking by braille” scars on it, too.) I doubt she ever got it warm enough to really blast all the moisture out of the block (and, and the main thermostat was bad, too, when i got it, so it was running cold all the time until I replaced that) or even for the choke to shut off. All that carbon has been building up in there for 30 years. I am afraid to pull the plugs, now, and see how carbon fouled they are…
I dug and I dug down into that crap until I got to the bottom, then stole some Q-Tips from the wife’s makeup table, soaked them with carb cleaner and rooted around in the manifold heat valves. (There must be a better tool for this….) Once I had gotten it as clean as it was gonna get, I put the t-stat assembly back together, cranked it and let it run while I cleaned up my tools. Sure enough, after about ten minutes, the base of the t-stat was too hot too touch, and the choke was slowly starting to open.
I think we’ve turned a corner, here, gentlemen.
I think, if that guy sends me the other t-stat, I will go ahead and replace it, because it never did seem to get the choke plate as lean as I thought it should be once it was warm, but at least I think I tackled the root of the problem.
I only called Mike about six times today, which I hope he didn’t find too annoying. Mike, if your reading this, there’s another dinner in this for you.
It’s been a good day, with some interesting discoveries. I really like dinking with this Dart.
I also spent way too much time trying to put an oversized oil plug in Mrs. Dog’s Honda today, which was not much fun. At all. And it’s still not right enough to suit me. Those Honda oil pans are fucking shitty.
Fixer, I am going to look into that Edelbrock carb/intake combo after I fix dinner. I will let you know what I find out.