It's like a bad superhero. Runs fine and dandy during the day but then if I try to run it at night it constantly stutters in 1st and 2nd gear at lower RPMs, I know that's normal but it doesn't happen during the day. Temperature doesn't affect the stuttering, could be freezing during noon it will run just fine, and could be warm at night and it still stutters, and car does it both when the engine is cold and warmed up.
Carb was just tuned up, I cleaned it, changed the air filter and even poured in STP fuel cleaner to see if that would fix it, still does it.
Carburted car runs fine while it's day, stutters at night
- Thread starter Glam_Stachee
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The only difference between day and night would be your lights, does it do it at night if you turn the headlights off.
Originally Posted by Duffyjr
The only difference between day and night would be your lights, does it do it at night if you turn the headlights off.
What car? What type of ignition system? I'd look at everything spark plug wires, cap and rotor esp. If it has points, check them, file and gap them. Might try a new condenser. Day night thing does not make sense unless its a load like lights , a/c that the alternator can't handle and lowers power to the coil, but thats a stretch.
Originally Posted by spasm3
What car? What type of ignition system? I'd look at everything spark plug wires, cap and rotor esp. If it has points, check them, file and gap them. Might try a new condenser. Day night thing does not make sense unless its a load like lights , a/c that the alternator can't handle and lowers power to the coil, but thats a stretch.
Originally Posted by Glam_Stachee
It's like a bad superhero. Runs fine and dandy during the day but then if I try to run it at night it constantly stutters in 1st and 2nd gear at lower RPMs, I know that's normal but it doesn't happen during the day. Temperature doesn't affect the stuttering, could be freezing during noon it will run just fine, and could be warm at night and it still stutters, and car does it both when the engine is cold and warmed up.
Carb was just tuned up, I cleaned it, changed the air filter and even poured in STP fuel cleaner to see if that would fix it, still does it.
Originally Posted by Pelican
Originally Posted by Glam_Stachee
It's like a bad superhero. Runs fine and dandy during the day but then if I try to run it at night it constantly stutters in 1st and 2nd gear at lower RPMs, I know that's normal but it doesn't happen during the day. Temperature doesn't affect the stuttering, could be freezing during noon it will run just fine, and could be warm at night and it still stutters, and car does it both when the engine is cold and warmed up.
Carb was just tuned up, I cleaned it, changed the air filter and even poured in STP fuel cleaner to see if that would fix it, still does it.
Are you sure it's an engine issue?
Could it be a drive line issue that manifests during a more humid night?
Clutch chattering or skipping when it's damp that you don't see during more dry conditions?
If it is an engine issue, I'm thinking marginal HT leads / spark plug wires depending on which version of English car part names you use.
I'd certainly look into cap, rotor, wires/leads and maybe even the plugs.
If it all checks out, and voltages are good with the lights on as others have suggested, start looking for other issues such as a chattering clutch or similar.
Check spark plug wires and boots for dry/cracking or arc tracks. If they're old replace them. Check engine ground strap and ignition electronics to ensure a good clean ground connection. Misfire can only be fuel or ignition and you've eliminated fuel. The electronics with a nominal ground wont fire well and old wires/boots can arc across their surface.
What about humidity ?
Edit : way too late 
Carb adjustement is finicky on these
Carb adjustement is finicky on these
Last edited:
Originally Posted by Popsy
What about humidity ?
Edit : way too late
Carb adjustement is finicky on these
Carb adjustement is finicky on theseOriginally Posted by javacontour
Are you sure it's an engine issue?
Could it be a drive line issue that manifests during a more humid night?
Clutch chattering or skipping when it's damp that you don't see during more dry conditions?
If it is an engine issue, I'm thinking marginal HT leads / spark plug wires depending on which version of English car part names you use.
I'd certainly look into cap, rotor, wires/leads and maybe even the plugs.
If it all checks out, and voltages are good with the lights on as others have suggested, start looking for other issues such as a chattering clutch or similar.
Not complicated, just that it tends to need adjustment often. Again my experience based on a 205 so I don't know, more space under the 309's hood so maybe less prone to need adjustment ?
Also there was two types of carbs on these, Solex and Weber. Solex apparently harder to tune ?
Had a similar problem many years ago and what we did was open the hood in a dark area and watched tiny sparks flash intermittently on the plug wires; Next day we misted the wires and the engine shook and stalled.
Ignition would be my guess, too, if it gets significantly more humid at night.
Have you ever opened the hood while it's running at night? If the plug wires are really bad, you might see them arcing in the dark.
Originally Posted by Popsy
Not complicated, just that it tends to need adjustment often. Again my experience based on a 205 so I don't know, more space under the 309's hood so maybe less prone to need adjustment ?
Also there was two types of carbs on these, Solex and Weber. Solex apparently harder to tune ?
Originally Posted by eljefino
Stuttering's an ignition issue.
I replaced the factory carb on my 1985 dodge plow truck last year. The new one works great. They are a wear item that wears out, and all the adjusting in the world won't make up for that.
Originally Posted by Rhymingmechanic
Ignition would be my guess, too, if it gets significantly more humid at night.
Have you ever opened the hood while it's running at night? If the plug wires are really bad, you might see them arcing in the dark.
Do what @dinoburner said and wet down the ignition parts then test drive. Look for cracks in the cap or coil. The voltage may not be high enough to spark over a bad spot when the engine is idling, it goes up under load. Bad wires really can't be identified by looking.
I agree with everyone else, humidity is a possible difference. At night (and in the dark), can you see any arcing on or around the wires when it is running poorly?
Wires? Throttle plate icing? Vacuum advance off? On a car old enough to have a carb, it could be anything
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