Hard Start...Idle Mixture or Timing?
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From: South Florida
Hard Start...Idle Mixture or Timing?
Could Idle Mixture being too lean (i.e. Q-Jet screws not turned out far enough) cause a little harder than normal start?
...or maybe timing too far advanced? Thoughts?
...or maybe timing too far advanced? Thoughts?
Thread Starter
Instructor
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From: South Florida
Originally Posted by 71redskin
starting issues are usually ignition you'd only notice lean condition when its running... hope this helps
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From: Lakeland Florida
I think more information is needed.
What type of hard starting are you having.
Is this from a cold engine or a hot engine.
Is it cranking over for a long period of time befoe starting.
Do you have to continually pump the pedal to get gas to the carb before it starts.
Does the motor slowly turn over with what seems like 1 second pauses before it finally gets going.
It could be timing in some cases, fuel deliver problems in others.
kdf
What type of hard starting are you having.
Is this from a cold engine or a hot engine.
Is it cranking over for a long period of time befoe starting.
Do you have to continually pump the pedal to get gas to the carb before it starts.
Does the motor slowly turn over with what seems like 1 second pauses before it finally gets going.
It could be timing in some cases, fuel deliver problems in others.
kdf
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From: South Florida
SEE RESPONSES INLINE
The car starts perfectly when hot.
Originally Posted by kdf1986
I think more information is needed.
Is this from a cold engine or a hot engine. COLD START
Is it cranking over for a long period of time before starting. 6 SECONDS
Do you have to continually pump the pedal to get gas to the carb before it starts. YES - AND CARB IS REBUILT RECENTLY
Does the motor slowly turn over with what seems like 1 second pauses before it finally gets going. NO - when it fires it fires
kdf
Is this from a cold engine or a hot engine. COLD START
Is it cranking over for a long period of time before starting. 6 SECONDS
Do you have to continually pump the pedal to get gas to the carb before it starts. YES - AND CARB IS REBUILT RECENTLY
Does the motor slowly turn over with what seems like 1 second pauses before it finally gets going. NO - when it fires it fires
kdf
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From: Lakeland Florida
If it starts harder when the engine is cold, I would consider the carb to be part of the problem.
Start with the simple stuff like the fuel filter. I read an article in my Holley magazine about this being a problem with fuel delivery.
There should also be some type of adjustment or float bowl setting to insure that there is enough gas in the carb to facilitate starting. If not, then pumping the gas pedal to push enough gas from the fuel pump to the carb would cause hard starting until there was enough fuel available to start the car.
Other than this quick answer, I am waiting to see what other replies come from a cold start condition.
kdf
Start with the simple stuff like the fuel filter. I read an article in my Holley magazine about this being a problem with fuel delivery.
There should also be some type of adjustment or float bowl setting to insure that there is enough gas in the carb to facilitate starting. If not, then pumping the gas pedal to push enough gas from the fuel pump to the carb would cause hard starting until there was enough fuel available to start the car.
Other than this quick answer, I am waiting to see what other replies come from a cold start condition.
kdf
Thread Starter
Instructor
Joined: Jan 2006
Posts: 223
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From: South Florida
Originally Posted by kdf1986
If it starts harder when the engine is cold, I would consider the carb to be part of the problem.
Start with the simple stuff like the fuel filter. I read an article in my Holley magazine about this being a problem with fuel delivery.
There should also be some type of adjustment or float bowl setting to insure that there is enough gas in the carb to facilitate starting. If not, then pumping the gas pedal to push enough gas from the fuel pump to the carb would cause hard starting until there was enough fuel available to start the car.
Other than this quick answer, I am waiting to see what other replies come from a cold start condition.
kdf
Start with the simple stuff like the fuel filter. I read an article in my Holley magazine about this being a problem with fuel delivery.
There should also be some type of adjustment or float bowl setting to insure that there is enough gas in the carb to facilitate starting. If not, then pumping the gas pedal to push enough gas from the fuel pump to the carb would cause hard starting until there was enough fuel available to start the car.
Other than this quick answer, I am waiting to see what other replies come from a cold start condition.
kdf
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Thread Starter
Instructor
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From: South Florida
Originally Posted by Kalway
Retard your timing a couple of degrees, if this fixes it, then that's probably your problem. If your q-jet hasn't been rebuilt in a long time, it may be leaking the fuel out of the bowl.
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From: San Diego CA
Originally Posted by Eric79-L48
It has been rebuilt just recently - what would cause the fuel leakage from the bowl assuming that is the issue?
The majority of parts on my engine are new so I haven't had to deal with leaky stuff in awhile.
Safety Car
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From: Lakeland Florida
Originally Posted by 68coupe
Holley has a magazine?
Thanks,
Joe
Thanks,
Joe
Some other books were:
How to rebuild your small block chevy.
Joh Lingenflter on monifying small block chevy engines
Rochester Carburetors.
So I dont know if you call this a book, or a magazine.
kdf
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From: Lakeland Florida
Originally Posted by Kalway
Generally fuel leakage is only a problem on old and tired q-jets. If yours is pretty fresh that shouldn't be a problem. If you suspect it is, one day, after it sitting overnight, take the airhorn off the top and see if the bowl is low/empty. I forget what causes leakage usually, since I've never had the issue and can only go off of second hand knowledge.
The majority of parts on my engine are new so I haven't had to deal with leaky stuff in awhile.
The majority of parts on my engine are new so I haven't had to deal with leaky stuff in awhile.
There was something written that a suckback condition may exist where the fuel is drawn back into the fuel pump, and it will siphon the gas out of the bowls if the jets or rods ( I forgot exactly what) were not seated correctly. This would cause the bowls to be empty the next day.
I will see if I can find that section and write it up as a possibility.
kdf
Thread Starter
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From: South Florida
Originally Posted by Kalway
Retard your timing a couple of degrees, if this fixes it, then that's probably your problem.
Safety Car
Joined: Jun 2004
Posts: 4,652
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From: Lakeland Florida
Hello,
Glad to hear that you were able to fix this. So you adjusted the timing and then had problems starting? It sounds like going back to the last known good position then fixed the problem.
But then again it was only 4 hours. I guess waiting until tomorrow morning will really be the test.
kdf
Glad to hear that you were able to fix this. So you adjusted the timing and then had problems starting? It sounds like going back to the last known good position then fixed the problem.
But then again it was only 4 hours. I guess waiting until tomorrow morning will really be the test.
kdf
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From: Lakeland Florida
Originally Posted by kdf1986
There was something written that a suckback condition may exist where the fuel is drawn back into the fuel pump, and it will siphon the gas out of the bowls if the jets or rods ( I forgot exactly what) were not seated correctly. This would cause the bowls to be empty the next day.
I will see if I can find that section and write it up as a possibility.
kdf
I will see if I can find that section and write it up as a possibility.
kdf
Bad fuel pump. If you have a fuel pump with a slightly leaky check valve in it, the fuel standing in the column between the pump and the carb will drain back down through the pump after engine shutdown. Since the needle/seat in the Q-Jet is in the bottom of the float bowl, this drain-back action will actually siphon the fuel right out of the carb float bowl. I have seen many brand new fuel pumps with leaky check valves in them.
kdf