Winter Worries

[83kid]

Hi,
So im a little concerned with starting my truck in the winter.
Got it a few months ago, so i havent had it in real cool weather.
I live in New England, so the winters can get pretty cold, nothing extreme.
I have an 83 k10 with a 350, MSD ignition and a mild cam also with a Edelbrock carb.
When i got it i brought it to a mechanic my father is good friends with, as i was having a few little problems with the choke.
The PO had disconnected it, for what reason i have no clue, so the mechanic fixed that and "tuned" the carb for warmer weather, as i got it just after winter, the PO saying it was tuned for colder conditions.
What is included in "tuning" a carb for the different weather conditions? I havent done much with carbed V8 engines at all, so im new to it.
Could i do this pretty easily on my own?

Also, how is the electric choke supposed to work?
For the most part, particularly on colder days or if the truck hasnt been started in a day or 2, i have to give the gas pedal a easy pump as im cranking it, and i just rev it a little till it gets warm, then it runs perfect.

How much trouble should i have starting in the mornings in winter?
Its my daily driver, so ill need it to start everyday, and people constantly talk of how hard it is to start these trucks in the winter. How do all you think itll be?

Thanks!

 

[77 K20]

should just be a little bit of trial and error to see how your truck responds to cold mornings. Some of my trucks just wanted a quick pump of the gas pedal then it would start right up. Others needed 2 or 3 pumps then they would start.

The first pump sets your choke. An electric choke after that is automatic. When you turn the key on it starts running electricity thru a coil on the carb. That starts heating it up, and as it expands the metal it starts moving a choke rod and opens the choke of the carb itself.

If you do get a real cold snap you can always buy an electric oil pan heater (provided your oil pan isn't an oil soaked greasy mess). I've had those and engine block heaters and prefer the oil pan heater. Easy to install... just crawl under and stick it to the pan (it is magnetic).

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[83kid]

So does the electric choke turn on when the key is on crank or on the on position?
How does pumping the gas pedal set the choke?


Thanks!

 

[77 K20]

I believe it sends voltage out with the key simply in the "on" position.

By fully depressing the gas pedal before you start cranking the engine it trips one of the linkages and the choke spring then allows the choke to close and sets the fast idle cam. This also then dumps some fuel down the carb from the accelerator pump so it will be ready to start. As the choke spring warms up a bit the fast idle cam will jump down to a lower setting, and the RPM will decrease a bit.

If after a few seconds of cranking and nothing happens, then I stop cranking the engine and give the gas pedal another pump.

If for some reason you flood the carb, keep the gas petal floored and then crank it. This opens the choke wide open and will clear out all the excess gas.

 

[350runner]

Over the winter months you'll find the factory air cleaner to help a lot by supplying hot air off the headers or manifolds. This is what I use and stand by it.

Sent from the dust in front of you!

 

[MadOgre]

I have a round chrome air cleaner and it works just fine in -40 weather with the winter front all closed up.

I always put a new block heater in every couple years, and use it.

 

[77 K20]

Took me a while to find this. Some basic troubleshooting of carbs/chokes:

The following troubleshooting tips are based on an otherwise correctly tuned engine, where the choke circuit has been determined to be the cause of the problem. The stated symptom can only be applied to a condition that calls for the choke to be evoked (not a hot engine problem).

Hard starting: Check to verify that the choke plate is closing fully when the gas pedal is tapped and that the plate maintains spring tension when closed. If the choke does not close, then either the linkage is gummed up, the air horn is warped, or the spring tension is too loose or the choke spring has experienced a failure such as an internal break.

Starts and stalls within a few seconds: If the choke plate closes properly and the engine starts and stalls almost immediately, the issue is usually not choke-related. This condition is likely the result of the carburetor float bowl losing fuel when the engine is turned off. The needle valve may be leaking under the gasket or the bowl may have a leak that drains it. This was common with Rochester carburetors, when the well plugs would leak, and with Carter designs when the sealing ball in the main circuit did not seat properly and allowed fuel to pass. The engine stalls because it is running out of gasoline in the carburetor.

Loads up/blows black smoke after running a few minutes: The choke plate is not opening enough after the engine starts. This can be caused by a misadjusted pull-off, a worn diaphragm in the pull-off that has either torn or has swelled and is not moving enough, or a fast-idle speed that is set too low. It is common to find all of these things wrong with an older carburetor.

Balky during warm-up; may spit/pop through the carburetor when trying to drive: The choke spring tension is not tight enough and the butterfly is opening prematurely, creating an excessively lean air/fuel ratio for the engine temperature. Choke spring tension needs to be made tighter.

Stays on fast idle too long: The choke spring tension is too tight, the heat source is not being supplied or is blocked, or the fast-idle cam is gummed up, bent or has another problem that does not allow it to drop.

A properly set choke circuit will allow the engine to fire immediately on even the coldest day; the fast-idle cam will drop one notch within a few seconds, allowing the transmission to be placed in gear and the vehicle driven away with no hesitation under any load or condition. Anything other than these results, and your carburetor choke is not set properly. By following the steps provided here, your engine will run with the best Detroit EFI system.

 

[chengny]

So does the electric choke turn on when the key is on crank or on the on position?

The electric choke (heater) begins to open the choke as soon as engine oil pressure is established. The choke will already be closed - it snapped shut when you depressed the accelerator to the floor. See below.

How does pumping the gas pedal set the choke?

There is a thermostatic coil attached to the choke plate shaft. When the coil is cold it imparts a closing torque on the choke plate shaft. But nothing moves because the shaft and plates are locked in position by the throttle linkage.

When you go out and press the gas pedal to the floor, the throttle linkage moves clear of the choke linkage and the choke plates are free to snap closed. As soon as you start your engine (and oil pressure reaches 10 psi) power flows through the oil pressure switch and over to the choke heater. At that point the thermostatic coil begins to heat up and now the torque on the choke plate shaft is reversed (in the opening direction) and the choke begins to open.

 

[350runner]

I have a round chrome air cleaner and it works just fine in -40 weather with the winter front all closed up.

I always put a new block heater in every couple years, and use it.

Question is can you start up and take off or do you have to sit and let it warm up? If the carb isn't a lil on the rich side the cold air will cause a lean condition. Trust I went through two engines b4 finding out why.

Sent from the dust in front of you!

 

[MadOgre]

Who jumps in a cold vehicle at -40 and starts and goes ? LOL

 

[MadOgre]

Question is can you start up and take off or do you have to sit and let it warm up? If the carb isn't a lil on the rich side the cold air will cause a lean condition. Trust I went through two engines b4 finding out why.

Sent from the dust in front of you!

???

 

[350runner]

If you supply hot air to the engine you'll see what I'm talking about. It will dramatically reduce your warm up wait time.

Sent from the dust in front of you!

 

[MadOgre]

If you supply hot air to the engine you'll see what I'm talking about. It will dramatically reduce your warm up wait time.

Sent from the dust in front of you!

Ok if you like driving a popsicle with frosted windows down the road. And don't mind running into things because you cant see anything. Not to mention all the other frozen parts on your vehicle.

Sorry but you don't jump into any vehicle at -40 and drive away, unless you had it parked in the garage, in which case its a non issue.

 

[350runner]

Your missing the point...

Sent from the dust in front of you!

 

[MadOgre]

Your missing the point...

Sent from the dust in front of you!

Not really

At -40 it needs to warm up regardless. That's the point.