SCToy, if your dieseling with the factory carb it's most likely the idle shut off solenoid. But I could be wrong because I wanna say the 81's didn't have one.

When I was searching around and researching on which weber to buy, I stayed away from the 34 because too many issues with them (mostly the heep crowd) and because of the lack of tuning kits for them as the jets and whatnot are hard to find.

 

I really don't have any experience with carbs so I have no idea, this is my first. I consistently have a problem with a high idle one taking my foot off the gas that will go back down to 900-1000 when I fiddle with the peddle, pulling it all the way up. When I look under the hood after pushing on the gas I see that the throttle sticks a before it is all the way closes. Very weak spring. I've also noticed that if I fiddle with the peddle and try to get the idle to return to normal before shutting it off that it doesn't diesel. (This may just be coincidental, but I am pretty sure that it's consistent).
I didn't even know there was such a thing as an idle shut off solenoid, so hardly in any position to diagnose that. Just what I've noticed.

 

I had problems with the dieseling with 84 22r and weber 38 i adjusted the timing and it helped but it still does it. Weak throttle return spring?

 

im going to seafoam it tomm and i will report back my findings!

 

if i wanted to lean it out a bit would i turn the idle mix screw in or out? is that the only adjustble mixture screw on the carb?

thanks guys

 

yes only adjustable mix on the carb, lean it out turn in richen turn out.
But you should follow this to set that screw: http://www.redlineweber.com/html/Tec...lean_best_.htm

 

so today i put 3/4 can of seafoam in the gas tank and sucked the rest through the intake. Is was a smoke show, put everything back together and went for a well spirited drive to clear it out. got back home shut her off and died right away! I was thinking this was too good to be true!!! so i drove around a bit more shutting it off from time to time with no problems......... until i got home shut it off for the last time of the day and it tried to keep running(not as bad as before) then coughed out the intake and died. Needless to say i was a little disappointed because i thought it was cured, maybe a couple more seafoam treatments will do the trick, im going to do it again tomm!

 

ok more updates for anyone who cares, i bought a inductive clamp for my fluke 88 so i could actually tell what the idle speed was.....it is was about 1000-1100, i have the idle screw on the carb backed all the way out so i adjusted the timing a bit to lower the idle to about 900-950 and it shuts off when i turn the key off, I had the timing set about 8 degrees prior to this and i didnt shoot the light at it this time but it runs and drives fine no knocking.

Why is my idle screw all the way out to get it to idle low enough? i cant find any vacuum leaks throttle cable seems to be adjusted properly. what else would cause this?

 

on a side note i just bought about 400.00 dollars worth of parts from lc engineering and toyota to fix my headgasket that is leaking externally and replace my timing chain....cant wait to dive into that!

 

8 degress IMO it too much considering OEM is 0.

Have you checked to see if the linkage is binding or the return spring isn't closing the throttle all the way? I had to add a return spring to mine. A throttle cable too tight will also cause this as well.

Another thing you can try which is very often overlooked. Take your hose off the PCV valve and block the hose. Does your idle lower back down?

 

i forot to mention i did add a return spring...i will check the pcv system next.

thanks

 

Best bet is to block off the factory manual pump and get a fuel pump rated at 3psi or whatever it is.
The problem your having is that your engine is running hot, but your still getting fuel into the engine.
Hence the dieseling.
So if you cut the fuel supply with the key (fuel pump) it should fix your problem.
However, my best guess is that when you "desmogged" your engine, you took out the idle cut solenoid, or fuel cut solenoid. Whichever we have.