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Idling very very high

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Pipemaster Hunter Nelson
Taylors, SC, USA   USA
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Jeff told me to post some pictures of a few components on my carb and see what all of you think. When i start the car it idles very very high and the idle screw is pretty loose so. I mean could it be diaphragm placement or throttle linkage problems? This shouldnt be hard to solve just kinda scary when its idling at 4000 RPMs


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76lucas Avatar
76lucas Gold Member Josh L
Christiansburg, VA, USA   USA
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1978 MG Midget 1500
1979 MG Midget 1500 "Blue "parts" Car"
2013 Toyota Camry "Boring Daily"
The amount of slack in the throttle cable indicates that the butterfly valve is not closed all the way. Has for why I am not sure. But you seem to be missing a spring. It goes on the same shaft has the other spring just on the other side of the throttle linkage.



If you never try to do it You will never be able to do it


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Dutch 1960 Avatar
Dutch 1960 Mark Holland
San Diego, CA, USA   USA
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If the butterfly is closing all the way, then it is probably in the fast idle circuit. John Twist gas a series of 3 YouTube videos that walk through that part of the carburetor assembly. There is no manual choke like on the older cars, but there are kits for manual chokes, which might be the way to go if the issue is in there. The repair of those automatic guys seems to be very tedious. My real world experience is not so clean and tidy as John's. Make sure that is the issue first. No more three things being changed out at once.

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Pipemaster Hunter Nelson
Taylors, SC, USA   USA
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In reply to # 3431916 by 76lucas The amount of slack in the throttle cable indicates that the butterfly valve is not closed all the way. Has for why I am not sure. But you seem to be missing a spring. It goes on the same shaft has the other spring just on the other side of the throttle linkage.

If i pushed the throttle linkage down, would that be kinda like a test to see if thats the issue? Because, this actually used to not happen. It happened after about the 4th time i took the carb off the car

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76lucas Avatar
76lucas Gold Member Josh L
Christiansburg, VA, USA   USA
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1978 MG Midget 1500
1979 MG Midget 1500 "Blue "parts" Car"
2013 Toyota Camry "Boring Daily"
You could try that just don't force it. If it wont move than you will need to find out if the linkage is bound up or if the fast idle is not working correctly. If it does move than you need to figure out why it won't come back to the closed position on it's own.



If you never try to do it You will never be able to do it

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Pipemaster Hunter Nelson
Taylors, SC, USA   USA
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In reply to # 3431926 by 76lucas You could try that just don't force it. If it wont move than you will need to find out if the linkage is bound up or if the fast idle is not working correctly. If it does move than you need to figure out why it won't come back to the closed position on it's own.

Well whats the fast idle? And, well ill try to close it but, i stuck a thin paintbrush in there and it seemed to be closed all the way as far as i could tell

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76lucas Avatar
76lucas Gold Member Josh L
Christiansburg, VA, USA   USA
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1978 MG Midget 1500
1979 MG Midget 1500 "Blue "parts" Car"
2013 Toyota Camry "Boring Daily"
Get a visual and be sure it's closed. You should be able to raise the piston and see the butterfly valve. The valve should be almost flat. Also have you ever had the auto choke off the carb? Did you ever get a light and set the timing incorrect timing can cause a high idle too.



If you never try to do it You will never be able to do it

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Pipemaster Hunter Nelson
Taylors, SC, USA   USA
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In reply to # 3431982 by 76lucas Get a visual and be sure it's closed. You should be able to raise the piston and see the butterfly valve. The valve should be almost flat. Also have you ever had the auto choke off the carb? Did you ever get a light and set the timing incorrect timing can cause a high idle too.

Well we got the timing close im pretty sure because if i move the dizzy only a little bit to either side the car about dies. But, ill use a mirror tomorrow and see if i can get a visual on the butterfly

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76lucas Avatar
76lucas Gold Member Josh L
Christiansburg, VA, USA   USA
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1978 MG Midget 1500
1979 MG Midget 1500 "Blue "parts" Car"
2013 Toyota Camry "Boring Daily"
Okay that works. I just want to make sure we have checked each thing before we move on to the next one.



If you never try to do it You will never be able to do it

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Pipemaster Hunter Nelson
Taylors, SC, USA   USA
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In reply to # 3431994 by 76lucas Okay that works. I just want to make sure we have checked each thing before we move on to the next one.

Yeah so from my perspective i doubt its a timing issue. But, i also think we forgot to put the diaphragm tab into the tab on the dashpot when we rebuilt it so Jeff told me that cause all sorts of problems so im gonna check that as well tomorrow

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Monsantiqu Avatar
Monsantiqu Anthony S
Kodak, TN, USA   USA
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Hi, as Mark alluded, it's most likely your fast idle circuit. This of course is operated by the "water choke."
They are really clever bits of engineering and are NOT very difficult to adjust. Get the proper information/specs for the Zenith/Stromberg carb and SYSTEMATICALLY adjust it. I would recommend buying a rebuild kit for the Autochoke and rebuilding that as well. It is easy and quite fun.
A manual choke IS an easier option as I have one on my car.
Enjoy!

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Pipemaster Hunter Nelson
Taylors, SC, USA   USA
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In reply to # 3432115 by Monsantiqu Hi, as Mark alluded, it's most likely your fast idle circuit. This of course is operated by the "water choke."
They are really clever bits of engineering and are NOT very difficult to adjust. Get the proper information/specs for the Zenith/Stromberg carb and SYSTEMATICALLY adjust it. I would recommend buying a rebuild kit for the Autochoke and rebuilding that as well. It is easy and quite fun.
A manual choke IS an easier option as I have one on my car.
Enjoy!

I noticed the one time i took the auto choke apart that the spring in there was pretty flimsy but it still worked and i dont think its the choke this time but i guess ill eliminate that when i get to checking it



Edited 1 time(s). Last edit at 2017-01-17 07:33 AM by Pipemaster.

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Monsantiqu Anthony S
Kodak, TN, USA   USA
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I have some awesome links. I will get them posted layer tonight.

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Pipemaster Hunter Nelson
Taylors, SC, USA   USA
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Well im reassembling my engine bay at the moment and after that im going to get into the carburetor and recenter the diaphragm and take a look at the water choke again possibly. Is it bad to drive it when its idling so high?

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JeffinMI Jeff Baran
Eagle, CO, USA   USA
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Hunter:

As when we talked, the carb stuff for me is not a great area, but I would NOT drive it around at that idle speed. There is a lot of energy that will go into the clutch material if you launch at that speed, and you will likely have some pre-mature wear. Might also cause some other issues as the torque spikes will go through the driveline. I would take the time to get it sorted to a reasonable value so another problem is not created setting you back even further.

I know when we quit working on the car yesterday, we did not hook up the tach wire. You should isolate that wire and see if you can get the tach working again (assuming it worked in the first place). I hope that it is still running so we can tackle the carb problem.

I would suggest, if someone here is a good tech resource on the carb to work through it step by step with them. This will certainly get you to the end point much faster. I would volunteer, but I am out of my league as I mentioned earlier.

Hope you get this sorted so you can be sure everything runs on a consistent basis. Hope you found the wiring issue under the dash on your lights as well.

Good to talk with you yesterday and you have my number if I can help. You can text to that number as well if needed. Its my work phone so sometimes I can't answer it during the day immediately.

Jeff



1972 MG Midget - Currently Under restoration

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