corvette choke starting procedure
Thread Starter
Advanced
Joined: Jan 2018
Posts: 92
Likes: 0
From: Brisbane, Australia
corvette choke starting procedure
Hi all,
Firstly apologies for asking a rookie question as this is my first carburetter car. 1969 corvette.
If i am cold starting the car, I pump the gas pedal a couple of times with the key in the on position and start the car. Does doing this automatically set fast idle? I know it sets the choke. I can disengage fast idle by blipping the throttle?
If I am warm starting (lets say the car was switched off 2 hrs earlier) the car I wont need to pump the gas pedal to set the choke? I can just start without touching the gas pedal?
If the car is somewhat warm and I set the choke then the choke spring will partially or fully open the choke valve depending on temp? Will the car still fast idle?
Essentially when should you apply choke and does fast idle automatically adjust itself?
Please let me know what the correct procedures should be for warm and cold starts.
Thankyou
Firstly apologies for asking a rookie question as this is my first carburetter car. 1969 corvette.
If i am cold starting the car, I pump the gas pedal a couple of times with the key in the on position and start the car. Does doing this automatically set fast idle? I know it sets the choke. I can disengage fast idle by blipping the throttle?
If I am warm starting (lets say the car was switched off 2 hrs earlier) the car I wont need to pump the gas pedal to set the choke? I can just start without touching the gas pedal?
If the car is somewhat warm and I set the choke then the choke spring will partially or fully open the choke valve depending on temp? Will the car still fast idle?
Essentially when should you apply choke and does fast idle automatically adjust itself?
Please let me know what the correct procedures should be for warm and cold starts.
Thankyou
Team Owner
Joined: Sep 2006
Posts: 31,214
Likes: 4,302
From: Westminster Maryland
Hi NJ,
There are starting procedures in the Owner's Manual.
They are for starting with a COLD engine.
Starting with a WARM engine.
Starting with an EXTREMELY COLD Engine.
Starting a FLOODED engine.
They all presume that the divorced choke is operating properly.
COLD.... Fully depress accelerator, slowly release, crank with foot OFF accelerator.
WARM ... depress accelerator about half-way and hold, while cranking.
EXTREMELY COLD....depress accelerator fully and release 2 or 3 times and then crank with foot off accelerator.
FLOODED engine.... depress and HOLD accelerator to floor while cranking.
Remember choke must be working. Have you been able to check it's operation with the engine both and at operating temperature?
Regards,
Alan
Choke in closed position, engine is COLD.
Choke in open position, engine is WARM.
There are starting procedures in the Owner's Manual.
They are for starting with a COLD engine.
Starting with a WARM engine.
Starting with an EXTREMELY COLD Engine.
Starting a FLOODED engine.
They all presume that the divorced choke is operating properly.
COLD.... Fully depress accelerator, slowly release, crank with foot OFF accelerator.
WARM ... depress accelerator about half-way and hold, while cranking.
EXTREMELY COLD....depress accelerator fully and release 2 or 3 times and then crank with foot off accelerator.
FLOODED engine.... depress and HOLD accelerator to floor while cranking.
Remember choke must be working. Have you been able to check it's operation with the engine both and at operating temperature?
Regards,
Alan
Choke in closed position, engine is COLD.
Choke in open position, engine is WARM.
Last edited by Alan 71; Mar 10, 2018 at 07:24 AM.
Safety Car
Joined: Dec 2012
Posts: 3,800
Likes: 1,712
From: Summerville SC
To add to the correct info that Mr. Alan has given you, make sure that when the choke is closed there is the correct gap between the butterfly and the carb body. I don't know what it is off hand, but when you get that number, find a drill bit that comes closest to that measurement. Place the bit between the two parts to keep the butterfly open that much. And DO NOT drop it into the carb!!! Then adjust your choke accordingly. Having the wrong gap throws everything else off. God luck.
Tech Contributor
Joined: Aug 1999
Posts: 14,375
Likes: 6,375
From: At my Bar drinking and wrenching in Lafayette Colorado
Lars
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
Hi all,
Firstly apologies for asking a rookie question as this is my first carburetter car. 1969 corvette.
If i am cold starting the car, I pump the gas pedal a couple of times with the key in the on position and start the car. Does doing this automatically set fast idle? I know it sets the choke. I can disengage fast idle by blipping the throttle?
If I am warm starting (lets say the car was switched off 2 hrs earlier) the car I wont need to pump the gas pedal to set the choke? I can just start without touching the gas pedal?
If the car is somewhat warm and I set the choke then the choke spring will partially or fully open the choke valve depending on temp? Will the car still fast idle?
Essentially when should you apply choke and does fast idle automatically adjust itself?
Please let me know what the correct procedures should be for warm and cold starts.
Thankyou
Firstly apologies for asking a rookie question as this is my first carburetter car. 1969 corvette.
If i am cold starting the car, I pump the gas pedal a couple of times with the key in the on position and start the car. Does doing this automatically set fast idle? I know it sets the choke. I can disengage fast idle by blipping the throttle?
If I am warm starting (lets say the car was switched off 2 hrs earlier) the car I wont need to pump the gas pedal to set the choke? I can just start without touching the gas pedal?
If the car is somewhat warm and I set the choke then the choke spring will partially or fully open the choke valve depending on temp? Will the car still fast idle?
Essentially when should you apply choke and does fast idle automatically adjust itself?
Please let me know what the correct procedures should be for warm and cold starts.
Thankyou
fi is easy, turn key. fuel is under pressure and squirted
into cylinder.
computer controls everything.
carbs need air drawn thru to suck gas into cylinder.
when an engine is cold it needs more fuel.
that is where the choke blocks air intake and creates a
more fuel mixture to fire engine.
each carb engine reacts a little different to how much
extra fuel mix it needs.
how cold etc.
this will be learned by you as time goes on.
pressing the gas pedal squirts raw gas into the manifold.
this is done by pistons called accelerator squirters.
these allow for gas to be injected for increase in rpm when throttle opened.
this is where the 1 or 2 pumps come in before starting.
too many pumps will flood mixture and cause hard starting.
then you will need to figure out how much gas pedal you need to use,
1/4, 1/8, 1/2 pedal for starting a warm engine.
when fully warm, no pedal at all may work.
again, depends on engine.
so, pressing pedal squirts gas.
opening pedal allows air and fuel to be sucked in.
you will figure it out.
Melting Slicks
Joined: Dec 2009
Posts: 3,229
Likes: 656
From: Thunder Bay
carbs and fuel injection are very different and starting is different.
fi is easy, turn key. fuel is under pressure and squirted
into cylinder.
computer controls everything.
carbs need air drawn thru to suck gas into cylinder.
when an engine is cold it needs more fuel.
that is where the choke blocks air intake and creates a
more fuel mixture to fire engine.
each carb engine reacts a little different to how much
extra fuel mix it needs.
how cold etc.
this will be learned by you as time goes on.
pressing the gas pedal squirts raw gas into the manifold.
this is done by pistons called accelerator squirters.
these allow for gas to be injected for increase in rpm when throttle opened.
this is where the 1 or 2 pumps come in before starting.
too many pumps will flood mixture and cause hard starting.
then you will need to figure out how much gas pedal you need to use,
1/4, 1/8, 1/2 pedal for starting a warm engine.
when fully warm, no pedal at all may work.
again, depends on engine.
so, pressing pedal squirts gas.
opening pedal allows air and fuel to be sucked in.
you will figure it out.
fi is easy, turn key. fuel is under pressure and squirted
into cylinder.
computer controls everything.
carbs need air drawn thru to suck gas into cylinder.
when an engine is cold it needs more fuel.
that is where the choke blocks air intake and creates a
more fuel mixture to fire engine.
each carb engine reacts a little different to how much
extra fuel mix it needs.
how cold etc.
this will be learned by you as time goes on.
pressing the gas pedal squirts raw gas into the manifold.
this is done by pistons called accelerator squirters.
these allow for gas to be injected for increase in rpm when throttle opened.
this is where the 1 or 2 pumps come in before starting.
too many pumps will flood mixture and cause hard starting.
then you will need to figure out how much gas pedal you need to use,
1/4, 1/8, 1/2 pedal for starting a warm engine.
when fully warm, no pedal at all may work.
again, depends on engine.
so, pressing pedal squirts gas.
opening pedal allows air and fuel to be sucked in.
you will figure it out.
Thread Starter
Advanced
Joined: Jan 2018
Posts: 92
Likes: 0
From: Brisbane, Australia
Thanks Alan for the procedure. I really need to get a copy of the owner's manual.
The choke appears to function correctly and had the fast idle set by my mechanic.
On cold start how long does it usually take for fast idle to drop back down to normal idle? I was advised to let the car warm up for 4-5 minutes
The choke appears to function correctly and had the fast idle set by my mechanic.
On cold start how long does it usually take for fast idle to drop back down to normal idle? I was advised to let the car warm up for 4-5 minutes
Last edited by NJey1985; Mar 18, 2018 at 03:45 AM.
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Melting Slicks
Joined: Dec 2009
Posts: 3,229
Likes: 656
From: Thunder Bay
I have a Holley 770 Street Avenger with electric choke. It works well, but the choke comes off too quickly. It starts well and runs well once its warm, but from about the two minute mark to about 7 or 8 minutes when its warm, it wants to stall. Adjusting the choke coil doesn't make a significant difference. Any way I can slow the choke coming off?
Pro
Joined: Dec 2011
Posts: 626
Likes: 15
From: Austin, TX
I have a Holley 770 Street Avenger with electric choke. It works well, but the choke comes off too quickly. It starts well and runs well once its warm, but from about the two minute mark to about 7 or 8 minutes when its warm, it wants to stall. Adjusting the choke coil doesn't make a significant difference. Any way I can slow the choke coming off?
Your coil might be defective though.
Tech Contributor
Joined: Aug 1999
Posts: 14,375
Likes: 6,375
From: At my Bar drinking and wrenching in Lafayette Colorado
I have a Holley 770 Street Avenger with electric choke. It works well, but the choke comes off too quickly. It starts well and runs well once its warm, but from about the two minute mark to about 7 or 8 minutes when its warm, it wants to stall. Adjusting the choke coil doesn't make a significant difference. Any way I can slow the choke coming off?
Lars
Melting Slicks
Joined: Dec 2009
Posts: 3,229
Likes: 656
From: Thunder Bay
The choke functions exactly as designed. It is an electric choke so there is no relationship between the actual operating temperature of the engine and the rate at which the choke comes off. On a high performance engine where we do not have an EFE valve and/or a heat crossover passage in the intake manifold, the engine warms up much more slowly. I have my choke set so that it is just off when the engine is at operating temperature. Problem is the rate at which it comes off. The choke comes off before the engine is warmed up. Holley should make choke coils that operate at different rates. I wonder if installing a resistor in line with the choke coil would slow down the warming. Anyone know enough about electronics to answer that?