sk8rlee

While trying to figure out why this truck doesn't run right I noticed that the choke butterfly valve doesn't stay closed. What happens (and it shows in the video) is that I'll take the choke linkage and hold it against the plunger (?) that pushes it open, it'll stay there for a few seconds and then just drop wide open. is there supposed to be a spring or something holding the linkage against that plunger/actuator thing? It can't be it's supposed to just fall wide open like that, huh? In the video the engine is warm, not normal operating temp but warm, but even with the cold engine that butterfly valve is wide open until I manually close it. Many thanks for any help y'all can give me.

I can't seem to embed this video, maybe someone here can help, but either way, here's the link for it.
http://www.youtube.com/watch?v=8rD7K...ature=youtu.be

83Toyota88

iTrader: (1)

I'm wondering if the choke thermostat has gone bad. I believe that controls the choke butterfly. Also when the engine is cold and off you should be able to push the pedal once to engage the choke or push the throttle linkage on the carb all the way back and push the choke butterfly shut and then release the throttle and the butterfly should stay in place to activate the choke. As the motor warms up the choke should slowly open the butterfly up. On the 22R there is "5 steps" the choke will go thought. Starts at max choke and slowly steps down (actually can watch it) as the motor warms up and eventually the last step is no choke.

These are pictures of a 22R choke but the same principles apply.

This is the choke on mine that controls the butterfly valve.




This is a bottom view of the butterfly and you can see the springs on the linkage you asked about.

83Toyota88

iTrader: (1)

Also the FSM on the 22R carb says the resistance of the spring coil in side the choke (measure between at the carb base where the choke is attached to the carb and the big wire on the choke opener) should be 19 ohms of resistance at 68 degrees room temperature.

Back to your video...you first force the choke shut and then it slowly opens and finally just fully releases. Then I saw you pushed it shut again and did the exact same thing. Pretty sure the choke shouldn't start all the way over again. It should fall back to a certain spot where it left off or go full open like the choke has been disengaged.

sk8rlee

Ok, so about the video, yeah, I keep forcing the choke shut because it runs good while it's still shut but once it falls wide open the idle drops so low that it sputters and almost dies (remember, the engine is still warming up in this video) but when it's at full operating temp it idles good so I'm assuming that it should still be choked for a little while longer and it's disengaging prematurely. Or is this how it's supposed to be and I just need to adjust the carb after the choke disengages? And maybe I should mention that when I first start it I pretty much have to keep pressing the gas pedal until it's warm. So I guess I should have made the initial post more of a question (is this how it's supposed to work?) instead of an implying that something might be wrong. And, for a little background on myself, I got my first car in '91, since then this truck is #12 or 13 and it's the first vehicle I've ever owned that has a carb so I know very little about them.

The problem I'm having that has me looking at this stuff is that when I drive it I can only take it up to about 35 or 40 mph and the engine dies and takes a lot of priming to get it going again. Gas is good and I replaced the fuel filter so my guess is that it has something to do with the carb.

Now to your pics, your carb is A LOT different than mine. The two valves, is that one for the choke and one for the throttle? And the choke thermostat, is that the dome shaped contraption on the right in the pic that, at least on mine, has what appears to be coolant hoses connected to it? It's kind of difficult for me to tell from the pic since it looks so much different than what I'm working with but if those 2 guesses are right it looks like your thermostat is connected directly to the choke valve? On mine the thermostat has a little 'L' shaped arm that pushes the linkage that controls the choke valve, it's not directly connected. That's what I'm doing in the video, pushing the choke linkage against the 'L' shaped arm from the thermostat. So even when the engine is cold when I push the gas pedal the choke valve just falls wide open. There's nothing to hold the linkage against the thermostat arm.

As for the springs, the only spring I have is shown in the pic below (please excuse my VERY poor photoshop skills) by the yellow arrow. The diameter of the wire used to make that spring is very thin, not very much bigger than the spring in your average clickable ink pen as compared to the springs in your pic and it doesn't look like it does much of anything. The green arrow is the linkage for the choke valve, the part I'm pushing on in the video. The red arrow is the part that contacts the throttle linkage and is responsible for the "5 steps" you mentioned. And the blue is the throttle linkage that the throttle cable is connected to. In this pic the choke is wide open, to close the choke valve you'd have to push the rod up rotating the whole thing counter-clockwise if you're looking at it straight down the head of that bolt. The red part also needs to be rotated counter-clockwise to contact the throttle link and do the "5 steps". So when the red part is as far as it'll go in the counter-clockwise direction the choke valve is also closed. As the red part goes through its five steps, slowly rotating in a clockwise direction, it gradually opens the choke valve and that all makes sense to me, it sounds like that's how it's supposed to work. The problem is that there's nothing to hold the red part against the throttle linkage, which in turn would push the choke linkage against the "L" shaped arm on the thermostat. Hot or cold when the gas pedal is pressed it falls to the position you see in the pic, which is choke valve wide open, meanwhile the the arm of the thermostat is doing it's thing slowly moving as if it were trying to slowly push the choke open.



I'm sorry if I seem to be talking in circles but it's the best way I can explain it without you standing next to me while it's happening.

83Toyota88

iTrader: (1)

That is definitely a choke problem.

Have you checked the timing of the motor? Also have you inspected your vacuum lines to see if they are dry rot and might be leaking?

One valve is for the throttle and one is for the choke as you say. The dome shaped thing is the choke for the thermostat. You are right on the 2 hoses going to the choke being coolant. Inside the the choke is a spring that will contract/expand depending on the temperature of the coolant. As for the springs I have posted some pics of a 20R carb so you can see for yourself. Hard to tell without being there.

I would strongly advise you learn to rebuild your carb or buy a re-manufactured one from someone like National Carbs. Here is the link for it assuming your truck is a 1980. You never said what year. Also replace all your vacuum lines.

http://www.nationalcarburetors.com/l...partnum=toy395

The other option is to de-smog your engine with a kit from LCE and get a weber carb kit from LCE.

http://www.lceperformance.com/Carbur...its-s/1341.htm

http://www.lceperformance.com/Block-Plates-s/1447.htm


Here are the 20R carb pics

83Toyota88

iTrader: (1)

Not sure why that one picture isn't working. You can click on it to look at it in Photobucket.

sk8rlee

Sorry, I thought I had my vehicle info in my sig. It's actually a '79. Would there be much of a difference? I haven't checked the timing, didn't think of it. And those pics will help a lot, especially the vacuum one, thank you.


Are these springs one in the same?

I would like to try to rebuild the carb but last time I looked I couldn't seem to fine any rebuild kits anywhere, not for mine. Any clues where I can look for these?

Thanks again!

83Toyota88

iTrader: (1)

The springs are the same ones. Rock Auto has a rebuild kit.