Testing my automatic choke

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xenos76
Posts: 10
Joined: Sat Mar 21, 2009 9:17 am
Car: Datsun B210

Post

Hey all,

I took out my carburetor to try to figure out why it is working improperly and I was thinking that the electric choke might not be working.While the engine was running, I disconnected the only wire that connects to it and nothing happend. Does anyone know how many volts I could send through the electric choke to test if it is working?This is the carb that I have:http://www.clutchkitcenter.com...6.pdf32/36 DGEV

The problem is that the colder it is outside, the longer it takes for my engine to crank and finally start up. So I am thinking that the automatic choke is not working at all.If it is broken, does anyone also know how I could fix it?Also I found out that I don't have a strainer where the fuel line is.
Modified by xenos76 at 7:26 PM 7/14/2009


ravera
Posts: 137
Joined: Mon Jul 06, 2009 8:30 pm
Car: 1971 Datsun 240Z

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Weber automatic choke, as many do, use a bi-metallic spring similar to a thermostat. When the engine has been off for a while, the spring is cold and it holds the choke on. When you start the engine it feeds +12 to the single contact (the carb is grounded to the rest of the motor so just put the -12 on the carb body) it slowly heats the bi-metallic strip causing it to un-coil and slowly open the choke. To see if it works, first see if it is in the "choke" position when it's cold, and then put 12v across it to see if it heats up. It wont be instant and it will probably take a few minutes, should be more when it's cold since the spring starts from a colder temp.

Bob

xenos76
Posts: 10
Joined: Sat Mar 21, 2009 9:17 am
Car: Datsun B210

Post

Ok I tried that and it works great. However, I just put my carb back together and it wont start. I think I may have done something wrong so the float doesn't work properly. From the guide I read, the distance from the top to the float at rest should be 51. My float was in the low 40's when I did it.Here is the guide I am looking at for my carb and I have the plastic one http://webernorthamerica.com/p...s.pdfI think I actually bent the piece of metal that touches the needle to change the height but I can't remember. I don't see how that "A" they label would change the height of the float.

ravera
Posts: 137
Joined: Mon Jul 06, 2009 8:30 pm
Car: 1971 Datsun 240Z

Post

To adjust, just bend the lil' tab. But when you try to turn it over, will it even start or will it not start at all? Because even if the float is too high it should still at least start, it may run like $hit, but it should still attempt to start.

xenos76
Posts: 10
Joined: Sat Mar 21, 2009 9:17 am
Car: Datsun B210

Post

Yeah I figured out what I did wrong I measured from the plate to the bottom of the float instead of the top. I thought it was way off so I bent the crap out of it. The bottom was 40mm from the bottom before and I bent it to 51 when the top should have been 51.Anyways, my car starts great now (so far) but I need to adjust the idle screws a little more because the car still runs a couple seconds after I turn it off.

Does my automatic choke open up when the key is turning the engine or can I just turn it to when the indicators turn on? I am wondering because when it is cold out, I would rather not break my starter trying to turn my engine over because my choke isn't opening.

ravera
Posts: 137
Joined: Mon Jul 06, 2009 8:30 pm
Car: 1971 Datsun 240Z

Post

Your choke should begin to open as soon as you put the key in the "on" position. Remember, the choke closed (which is the way it starts, and then slowly opens) is what you want for a cold engine. If you had the choke off (open) during a cold day, you would have one heck of a time trying to start it.

xenos76
Posts: 10
Joined: Sat Mar 21, 2009 9:17 am
Car: Datsun B210

Post

Well unfortunately I can't test the choke in cold weather right now as it is 90F outside right now. I was having a heck of a time starting in cold weather before and it would slowly start to work better the longer I would crank the engine.


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