Electric Choke/Cold Weather Running Problems
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
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From: Great Plains Iowa
Electric Choke/Cold Weather Running Problems
I must use my electric choke during the bitter cold winter months when morning temperatures can drop into the sub-teens. My engine would instantly start and fast idle but when I drove it my engine would continue to fast idle because the bitter cold fan wash would keep my choke housing cooled enough to keep the choke partially engaged. A hotter 195 degree thermostat helped some but only some so I got an idea about how I could add additional heat to the choke housing. Exhaust heat!
I modified my heat riser by slotting the butterfly with my air grinder and tapered carbide cutter and then pushed a piece of 1/4" steel tubing thru the housing. Then I ran a 2 foot piece of 1/4" neoprene hose from the heat riser to my choke housing so hot air could help warm the inside of the housing along with the electric heating element. With the additional heat from the exhaust my choke comes off and stays off so it appears the additional heat from the exhaust solved the problem.
I modified my heat riser by slotting the butterfly with my air grinder and tapered carbide cutter and then pushed a piece of 1/4" steel tubing thru the housing. Then I ran a 2 foot piece of 1/4" neoprene hose from the heat riser to my choke housing so hot air could help warm the inside of the housing along with the electric heating element. With the additional heat from the exhaust my choke comes off and stays off so it appears the additional heat from the exhaust solved the problem.
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Dec 21, 2015, 06:16 PM
Administrator
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From: About 1100 miles from where I call home.
I just got my new Carter fuel pump pressure switch installed so I'll take it for a 25 mile drive early tomorrow morning and see how it does. I'm pretty sure its being caused by the ram air after finding my carburetor was ice cold after a 60 mile drive a few days ago
And of course I'll be driving on my 24/20 psi under inflated tires to put a heavy load on my engine.
And of course I'll be driving on my 24/20 psi under inflated tires to put a heavy load on my engine.
Burning Brakes
Joined: Apr 2008
Posts: 1,222
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From: shelbyville West Michigan
am I seeing that correctly? hot exhaust gas on a hose laying directly on your fuel line?
that looks like an electric choke, are you saying the element cannot get hot enough to keep the choke open with air blowing from the fan?
that looks like an electric choke, are you saying the element cannot get hot enough to keep the choke open with air blowing from the fan?
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
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From: Great Plains Iowa
The electric choke was getting hot enough when the morning temperatures were in the 30's and 40's but when the temperature dropped into the teens the fan wash was enough to keep the choke housing so cold the choke was resetting itself during a 30 mile drive. I left my home one morning and drove to the valley below and found my engine was fast idling when I stopped at a red light and every red light thereafter that. I could kick the choke off but a short drive in the bitter cold air would reset it again. Hmm.
If you'll look closely the steel tubing goes all the way thru my heat riser so the exhaust gas is just getting the tubing real hot which makes the air flowing thru the tubing real hot. So its hot AIR going to my choke; not hot exhaust gas.
Back in the '50's and '60's the Chevrolets used "hot air" chokes. The ram horn exhaust manifolds had a 6" length of 5/16" steel tubing running thru the exhaust manifold at an angle that fed hot air to the choke housing. But over time the corrosive exhaust gasses (containing a lot of sulfur) ate the tubing up and then exhaust gas got blown into the choke housing which froze it up solid. That's when a coiled spring was set into a well in the intake manifold and that style was used thru the 1981's.
Last edited by toobroketoretire; Dec 18, 2015 at 12:52 PM.
Race Director
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I don't understand why a properly adjusted electric choke would need hot air to get it to open.
1. Is the choke adjusted so that on a 72 degree day it completely closes?
2. Where are you getting the 12 volts for the coil, from a dedicated spot on the fuse box or did you tap in to some other wire?
3. Prior to attaching the hose running to your heating pipe was that port on the carburetor left open or was it closed or connected to something else?
1. Is the choke adjusted so that on a 72 degree day it completely closes?
2. Where are you getting the 12 volts for the coil, from a dedicated spot on the fuse box or did you tap in to some other wire?
3. Prior to attaching the hose running to your heating pipe was that port on the carburetor left open or was it closed or connected to something else?
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
I don't understand why a properly adjusted electric choke would need hot air to get it to open.
1. Is the choke adjusted so that on a 72 degree day it completely closes?
2. Where are you getting the 12 volts for the coil, from a dedicated spot on the fuse box or did you tap in to some other wire?
3. Prior to attaching the hose running to your heating pipe was that port on the carburetor left open or was it closed or connected to something else?
1. Is the choke adjusted so that on a 72 degree day it completely closes?
2. Where are you getting the 12 volts for the coil, from a dedicated spot on the fuse box or did you tap in to some other wire?
3. Prior to attaching the hose running to your heating pipe was that port on the carburetor left open or was it closed or connected to something else?
My electric choke worked perfectly in warmer weather but when I recently installed a 180 degree thermostat and the outside temperature plummeted into the low teens I was finding my choke was resetting itself while I drove. I put the 195 degree thermostat back in and that helped but it didn't help enough as the bitter cold fan wash was resetting my choke. Chevrolet used "hot air" chokes from 1955 thru 1964 and it worked great BUT the corrosive exhaust gasses ate the 5/16" steel tubing in the exhaust manifold up which then allowed the exhaust gasses to enter the zinc choke housing; eating it up too! I'm simply using the heat from the exhaust to help the heating element keep the choke housing warm enough to resist the cooling effect of the fan wash.
I have a severe duty fan clutch and 7-blade fan so the amount of air pulled by the fan is enormous. When the outside temperature is just above zero degrees the cooling effect on the engine is tremendous; so tremendous the heating element in the choke housing just wasn't enough to keep the choke off during driving. It would when the engine was idling but not when it was running at a steady 2000 rpm.
Last edited by toobroketoretire; Dec 18, 2015 at 02:46 PM.
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
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From: Great Plains Iowa
Why Electric Chokes Suck In Very Cold Weather
My electric choke gets it's 12 volt power from my 10-gauge HEI input wire so it has plenty of power to feed it.
The problem with any electric choke is it "hangs in the wind" so to speak so it will cool off quickly. And as its sticking out in the wind the powerful fan wash will cool it enough to reset it while driving IF the air blowing around it is cold enough.
The intake manifold mounted coiled choke spring worked perfectly because the exhaust-heated intake manifold kept the coiled spring very hot long after the engine was shut down. Not so with an electric choke housing as its exposed to the air around it. The electric heating element can only produce so much heat and if bitter cold air is blasting against it the bitter cold air can easily offset any heat the element can produce. So an electric choke does have it's drawbacks.
In very cold weather an hour spent in a store is more than enough to reset an electric choke and the engine will once again fast idle. But it shouldn't fast idle after a 45 minute drive and that's what I was experiencing two days ago. My modified heat riser won't prevent fast idling after I have been in a store for an hour but it will help to reduce the fast idle time to a minimum as the exhaust heat will help it to warm up a lot quicker.
Last edited by toobroketoretire; Dec 18, 2015 at 03:56 PM.
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You do realize all Holley instructions concerning electric chokes say To Not get power from the ignition circuit? Below is one of many instruction sheets that state that.
http://documents.holley.com/199r7948-5rev6.pdf
http://documents.holley.com/199r7948-5rev6.pdf
Pro
Joined: Oct 2009
Posts: 664
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From: Marysville Ohio
My electric choke gets it's 12 volt power from my 10-gauge HEI input wire so it has plenty of power to feed it.
The problem with any electric choke is it "hangs in the wind" so to speak so it will cool off quickly. And as its sticking out in the wind the powerful fan wash will cool it enough to reset it while driving IF the air blowing around it is cold enough.
The intake manifold mounted coiled choke spring worked perfectly because the exhaust-heated intake manifold kept the coiled spring very hot long after the engine was shut down. Not so with an electric choke housing as its exposed to the air around it. The electric heating element can only produce so much heat and if bitter cold air is blasting against it the bitter cold air can easily offset any heat the element can produce. So an electric choke does have it's drawbacks.
In very cold weather an hour spent in a store is more than enough to reset an electric choke and the engine will once again fast idle. But it shouldn't fast idle after a 45 minute drive and that's what I was experiencing two days ago. My modified heat riser won't prevent fast idling after I have been in a store for an hour but it will help to reduce the fast idle time to a minimum as the exhaust heat will help it to warm up a lot quicker.
The problem with any electric choke is it "hangs in the wind" so to speak so it will cool off quickly. And as its sticking out in the wind the powerful fan wash will cool it enough to reset it while driving IF the air blowing around it is cold enough.
The intake manifold mounted coiled choke spring worked perfectly because the exhaust-heated intake manifold kept the coiled spring very hot long after the engine was shut down. Not so with an electric choke housing as its exposed to the air around it. The electric heating element can only produce so much heat and if bitter cold air is blasting against it the bitter cold air can easily offset any heat the element can produce. So an electric choke does have it's drawbacks.
In very cold weather an hour spent in a store is more than enough to reset an electric choke and the engine will once again fast idle. But it shouldn't fast idle after a 45 minute drive and that's what I was experiencing two days ago. My modified heat riser won't prevent fast idling after I have been in a store for an hour but it will help to reduce the fast idle time to a minimum as the exhaust heat will help it to warm up a lot quicker.
Had a 1976 L-82, 4-sp
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From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Agreed cooper9811, no one has this problem but him. Now, to help him out. TB, you need to pressurize the front choke housing housing to 24 psi and the rear to 20. That will increase the air temp inside with a nice linear temperature gradient decreasing from forward to aft in the housing. If this doesn't work for you, just adjust the damn choke like anybody else would do.
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
You do realize all Holley instructions concerning electric chokes say To Not get power from the ignition circuit? Below is one of many instruction sheets that state that.
http://documents.holley.com/199r7948-5rev6.pdf
http://documents.holley.com/199r7948-5rev6.pdf
That doesn't apply to the HEI's when the power is coming from the IGN terminal.
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
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From: Great Plains Iowa
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
The point of this thread is to inform you about how much your electric choke can be affected by the ice-cold wash of the fan. During the first 8-10 miles of driving and before the radiator heats up the bitter cold air being blown at the engine can prevent the choke housing from warming up enough to keep the choke off. In my garage with my hood open my choke was coming completely off but after 30 miles of driving in sub 30 degree weather I was finding my choke was still uh "choking" and causing my engine to fast idle at around 1000-1100 rpm.
That was with a 180 degree thermostat. A hotter 195 degree thermostat helped but not enough to prevent the choke from re-engaging while driving. That's why I am now trying the modified heat riser. I'll know more after I go to the valley early tomorrow morning to run some errands. Snow is being predicted where I live so tomorrow morning will be a good test. Wish me luck guys!
That was with a 180 degree thermostat. A hotter 195 degree thermostat helped but not enough to prevent the choke from re-engaging while driving. That's why I am now trying the modified heat riser. I'll know more after I go to the valley early tomorrow morning to run some errands. Snow is being predicted where I live so tomorrow morning will be a good test. Wish me luck guys!
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Take the choke off, mill the tower down and start it up and let it idle with your foot to modulate, have a smoke and coffee and you are ready to go.
Burning Brakes
Joined: Nov 2012
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From: Indianapolis IN
I think TBTR needs a new fan clutch. Damn thing shouldn't be engaged if it's that cold out !
Melting Slicks
Joined: Mar 2008
Posts: 2,989
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From: Meriden CT
That's me (no smokes tho'). Works in Indiana winters on a Qjet with most of the choke tower off and a radius to make a perfect circle over where the choke housing intrudes the primary bores.
I think TBTR needs a new fan clutch. Damn thing shouldn't be engaged if it's that cold out !
I think TBTR needs a new fan clutch. Damn thing shouldn't be engaged if it's that cold out !
Exactly, You'll never convince him though.
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
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From: Great Plains Iowa
Choke Resetting Itself As I Drive
Back in the '60's and '70's Ford, Mercury, and Lincoln used the 5/8" heater hose to keep the choke housing hot. The housing had a "U" clip attached to it and the heater hose was jammed into the "U" which transferred heat to the choke housing. And I have seen choke housings that were water heated (the water actually circulated thru it) but that didn't work well because the zinc casting corroded real bad. Had G.M. used stainless steel tubing in their hot air chokes they would have done well but as they used mild steel tubing the corrosive exhaust gas ate thru the tubing and then exhaust gasses entered the choke housing.
Snow is being predicted today so I'll make an early morning trip to the valley below and see how effective my modified heat riser is at adding heat to my choke housing. If it still comes back on as I'm driving it I'll try wrapping A/C putty around the choke housing.
Snow is being predicted today so I'll make an early morning trip to the valley below and see how effective my modified heat riser is at adding heat to my choke housing. If it still comes back on as I'm driving it I'll try wrapping A/C putty around the choke housing.