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Cold Start
Posted:
Sat Dec 14, 2013 9:28 amby Ethan
Ok so one issue I have that doesnt bother me just can be a tad annoying is when I first start up the old 112 I have to sit with my foot on the gas for atleast a couple minutes straight or it will die after about 20-30 minutes warming up to 187 degrees its perfectly fine and will start no problems, during the summer I dont recall having any issues cranking
Re: Cold Start
Posted:
Sat Dec 14, 2013 10:46 amby lbesq
You do not have a Throttle cable hooked up? That is one of the things it was used for. We have gotten used to "automatic" choke/throttle set ups on our new vehicles.
Re: Cold Start
Posted:
Sat Dec 14, 2013 10:55 amby Smog_guy
That's what the choke is for, cold starts.
If you remove the aircleaner you should see it on top.
It's operated by a cable on old vehicles (say pre-1960).
You want to hook it back up or address the cable binding issue or whatever.
A good place to start is to just see if you can move the choke open and closed with your fingers.
Re: Cold Start
Posted:
Sat Dec 14, 2013 11:53 amby Ethan
Smog_guy wrote:That's what the choke is for, cold starts.
If you remove the aircleaner you should see it on top.
It's operated by a cable on old vehicles (say pre-1960).
You want to hook it back up or address the cable binding issue or whatever.
A good place to start is to just see if you can move the choke open and closed with your fingers.
Mine doesnt have the throttle cable but my choke works fine I've just never used it lol I used it maybe a couple times when i first got it just to get fuel to my carb
Re: Cold Start
Posted:
Sat Dec 14, 2013 7:42 pmby lbesq
See if I state this correctly: Choke cable will help with the cold start, but once motor starts to warm up and you are right there, it will "kill" the motor. Throttle, once started with choke can be set out just a bit to take the place of the choke action(release choke) to keep it running till it warms completely up. Throttle would act as if you had your foot on the gas pedal "just a little" to keep it running once started. You should not have to set there.
That is how I remember it.
Re: Cold Start
Posted:
Sun Dec 15, 2013 12:20 amby MikeMiller/old
Most carbs have a fast idle cam, when the choke is closed it lifts the fast idle cam into position and bumps the idle speed up. The other thing to learn for those who didn't grow up using a manual choke, Pull the choke out and crank on the engine, as soon as it starts push the choke back in but not all the way. Leave it out about 3/4 of an inch for a bout 5 minutes until the engine warms up. This enriches the fuel mixture to compensate for poor atomization of the gas on a cold engine. MM
Re: Cold Start
Posted:
Sun Dec 15, 2013 10:41 amby Ralph Goff
I've always needed full choke to start any of my IH sixes even in summer. Once it starts I still leave it on partial choke for a while so the idle stays up. A cold engine needs a richer mixture to run. Back in the days of manual chokes we didn't depend on a computer to figure out those details.
Re: Cold Start
Posted:
Sun Dec 15, 2013 10:23 pmby rsr1957
I've haven't needed the choke to start up my truck, although I do try it at the start on really cold days. I end up just starting it the way we used to, using the gas pedal. But I do use the hand throttle when it starts until the engine warms up. Seem the choke on my truck isn't working correctly or whatever, pumping a couple of times on the pedal does the trick, but it is nice to have the hand throttle to use even on temperate days until the motor is running smoothly, and sometimes just to make sure the truck keeps running when parked while I'm dining my pre-trip inspections, adjusting the mirrors and all. Luckily for me the truck starts easily and when warmed up, runs nicely with the throttle all the way in. The choke may be helping me get the initial gas into the carb, but I find if I leave it on too long the truck actually takes longer to start up and kills itself almost immediately. In a way, I kinda like the fact that younger drivers can't seem to figure out how to start it, it's not like I have security systems on it and it cuts down the possibilities of joy rides, you get to know what works on older engines over time and use.
Re: Cold Start
Posted:
Mon Dec 16, 2013 7:06 amby Buzzman72
The choke does NOTHING to put gas into the carb. It simply restricts the amount of air going into the carb, resulting in a slightly richer fuel/air mixture. Pumping the gas only TEMPORARILY adds more fuel to the engine, as the carburetor's accelerator pump comes into play; when that temporary shot of fuel is run through the cylinder and exhausted, it's gone.
On cars and trucks that have slightly newer carburetors than our trucks, they have automatic chokes. To set an automatic choke to run, press the accelerator pedal to the floor ONCE and release. Besides adding a shot of fuel from the accelerator pump, this also brings the "fast-idle" cam on the carburetor into play. The fast-idle cam is connected to the automatic choke, and it prevents the throttle blade[s] on the carb from completely closing until the choke releases. These old trucks with manual chokes DO NOT HAVE a fast-idle cam on the carb; that's what the 'THROTTLE' knob is used for.
Physics class taught us that cold air is more dense than warm air. So for the fuel/air mixture to be stoichiometrically correct on a cold engine, more fuel must enter the engine, relative to the amount of air coming in. Otherwise, a lean fuel/air mix enters the engine, and the engine tends to "spit back" through the carb on acceleration.
There's a lot more to the subject than that, with the heat riser in the exhaust manifold coming into play as the engine warms up...but you first should understand how the carburetor functions before you can move on from there. It's not rocket science, but it IS science...mostly basic grade-school and high-school physics.
Re: Cold Start
Posted:
Mon Dec 16, 2013 9:31 amby Ethan
Buzzman72 wrote:The choke does NOTHING to put gas into the carb. It simply restricts the amount of air going into the carb, resulting in a slightly richer fuel/air mixture. Pumping the gas only TEMPORARILY adds more fuel to the engine, as the carburetor's accelerator pump comes into play; when that temporary shot of fuel is run through the cylinder and exhausted, it's gone.
On cars and trucks that have slightly newer carburetors than our trucks, they have automatic chokes. To set an automatic choke to run, press the accelerator pedal to the floor ONCE and release. Besides adding a shot of fuel from the accelerator pump, this also brings the "fast-idle" cam on the carburetor into play. The fast-idle cam is connected to the automatic choke, and it prevents the throttle blade[s] on the carb from completely closing until the choke releases. These old trucks with manual chokes DO NOT HAVE a fast-idle cam on the carb; that's what the 'THROTTLE' knob is used for.
Physics class taught us that cold air is more dense than warm air. So for the fuel/air mixture to be stoichiometrically correct on a cold engine, more fuel must enter the engine, relative to the amount of air coming in. Otherwise, a lean fuel/air mix enters the engine, and the engine tends to "spit back" through the carb on acceleration.
There's a lot more to the subject than that, with the heat riser in the exhaust manifold coming into play as the engine warms up...but you first should understand how the carburetor functions before you can move on from there. It's not rocket science, but it IS science...mostly basic grade-school and high-school physics.
Did all those trucks come with throttle knobs and mines just missing?