Carb dissassembled and put through the sand blaster. It would have been nicer to use bead media, but at $80 a bag I’ll give it a pass. 90 lbs pressure on the air hose and I believe I got all the sand out. I blocked off the fuel passages to keep some of the sand out. I also ran a brass wire through all the passages and blew them out again. Before blowing everything out I put it through the parts washer again.
Fortunately I have a donor carb. It will also be useful when it comes time to get all the springs, arms and levers back in the right order. Turns out this doesn’t seem to be a Stude carb, but no matter, it’s an AFB.
The Stude carb has the front setup with a cotter pin and spring in the auxiliary throttle. The spring was attached to the center of the venturie It seems to be a set up to help the flap the return the the rest position and/or to slow down its opening. In any event the donor carb’s aux throttle has much heavier return weights. So I’ll use that rather than the rinky-dink cotter pin & spring setup.
Unfortunately the carb cleaner didn’t free up both idle mixture screws. One broke off. So I drilled it out as much as possible without damaging the threads and used a small round file to open the hole up to the original size for threading. I then used a tap and it seemed to follow the original threads nicely. Sometimes you get lucky!
No matter how much I blew out the secondary throttle shaft it still felt catchy. Of course when I tried to get the brass screws out two broke off. Par for the course with these screws which is why I would have prefered to leave them in place. Fortunately I was able to drill and tap them out. The donor carb provided two replacement screws. No problem getting them out of the donor carb – go figure!
The throttle shaft was a bit rusty and that was the problem. So I ran it through the wire wheel and then sanded just enough to get the high bits off. It now operates nicely. I put the screws back in with red permanent thread locker as the screws were not long enough to counter punch and I didn’t want to chance bending the shaft anyway.
I tried to remove the jets without damage but, one became toast. I ground off a screw driver so that it fit the jet slot snugly. Still ended up screwing up the jets. I hoping to get two new primary jets from Stephen Allan’s otherwise I’ll be on a search!
The gaskets have been in place so long that the carb cleaner couldn’t loosen them fully from the aluminum body. So I used dental picks to scrape them off just like when the dentist scrapes off the plaque from your teeth. I get them for free from the dentist. They are the worn out tools. Just ask for them the next time you are in for a checkup. Handy for all types of jobs on old cars.
Lots of little bits to clean up before the re-assembly. Gaskets to be scraped off and screw heads to be polished with the wire wheel. Then bagged and kept together. Fortunately Stephen Allan’s were able to supply new primary jets for the 3589S to replace the damaged ones. The kit still hasn’t arrived, but that’s not an issue. I don’t plan to re-build the carb until I have it positioned on the engine and fitted to the gas pedal and the trans. The original AFB wasn’t designed cables to the gas pedal or the trans. Also, I’m working out the best way to add 1″ under the carb.