Hello, I have a Chevy 250 inline six with a rochester 1bbl carb on it. I just bought the carb like 2 months ago, it's a rebuilt one from holley. so it's been running awesome since i put it on and then the other day after i drive down the st. and park it to run into a store... it won't start. i played with everything for a while but couldn't get it going again. the plugs were all fouled and dirty, and they were only a few months old. someone told me this might be a choke problem? if it is, then what do i do to fix it? just change out the choke? it seems odd that the choke would have to be fixed this soon, but mayeb it was just faulty. any thoughts?
Yeah that's what i was thinking also, and i could change it out pretty easy but i am just worried that might not be it and then i am wasting money and time. i went out yesterday morning and it started right up after siting all night and ran fine, but then when i shut it off it wouldn't start back up again. it is definitely getting fuel, but not spark. if the choke is messed up would it foul the plugs that quick? i am about ready to smash it with a hammer.
You say your not getting Spark? Is that at the Plugs Or at the cap.? What dist. do you have.Points? or HEI?
When it refuses to start, remove the air cleaner and look at the choke to see if it is closed. There is an adjustment to cause the choke to open faster, I think. Stick a pencil in the choke to hold it open and see if it starts. If all else fails go to manual choke kit.
Your choke won't effect the spark. Once you have it running and warmed up, look at the choke plate to verify that it is open all the way. If not you maybe able to adjust it. But no spark, is an ignition issue, not the carburetor.
hey thanks, yeah i am getting spark now, the plugs were totally junk so i had to put new ones in. oh and i have HEI so if i leave it overnight and then come out in the morning it will start right up and run fine until i turn it off and then it won't start up again. I tried the screwdriver in the choke trick to get it going and that helps it a little but not totally. the choke seems to be ok when it is running, but then won't open again after it is shut off? i am wondering if maybe that idle solenoid thing could be the issue....anybody have any experience with those things?
That thing just keeps the throttle plates from closing right away when you chop the throttle. Gives the raw gas some air to burn with. I gave up fooling with the choke on my Stude and installed a hand choke. Admitting defete I know, but it always works.
Get yourself a good manual like a Chilton,Motors, or even a Haynes and read up on how your carb is supposed to work. Some points to keep in mind 1> The choke doesn't close all the way when the engine cools off , it closes til it hits the lowest stop of the choke or fast idle cam. Thats where it stays until YOU tap the gas pedal on a cold start up. THEN it closes to lightly against the edge of the air horn, thats choke full on position. You start the car and as the exhaust heat heats the choke actuator spring the choke "tries" to open but can only open til its linkage hits the fast notch of the fast idle cam. Now you are in a choke on fast idle condition while the engine heats up. When it does heat up you "tap"the gas pedal,,the fast idle cam drops out of the way and the spring tension stands the choke up in the airhorn to its full open position. 2> IF the plugs have fouled so bad it wouldnt start you need to make sure of what is doing the fouling. Could be gas, oil, even antifreeze/coolant. 3> IF its gas ,,,and I dont think it can be IF it runs smooth when warm, the carb is flooding. Try this for starters, disconnect and PLUG the fuel line to the carb , start the engine and let it run the carb dry ( til it stalls) This can remove junk and debris from the fuel bowl and needle/seat of the carb. replace the gas line and see how it runs hot and cold then. IF it doesnt want to start warm or hot after a shutdown,,,AND you are POSITIVE the spark is ALWAYS there you may be having a flooding condition develop AFTER you shut it off . Internal carb leaks can let gas drip and puddle onto the floor of the intake manifold, causes a flooded condition when you try to restart. This may be a result of leaking plugs in the carburator casting , or a way wrong float setting . or a faulty gasket in the carb body,, all things worth checking. Just some suggestions from an old guy that likes old Chev 6's , good luck
wire the choke open. it will still start and stay running with just a little more peddle action after it starts, i'm sure you know this. this will tell you if the choke is the problem. i never run a choke.
Do you have a heat tube type choke? Does it have a black cover that says rich-lean on it? Turn it to lean. Or is it somehow working backwards? Closing with heat?
whoa, thanks. that is some great info all around. you guys rule. norton, i am thinking it might be the latter issue you brought up with the gas pooling or at least something to that effect. it seems like it is flooded when i try to start it after the initial warmup. it runs awesome during warmup and starts right up the first time after it has sat for a day, but then after that...no go. it is just a huge bummer though because i just bought the carb and now it looks like i'll have to rebuild the thing. i should have just rebuilt my old one in the first place. i guess you have to learn from experience though.
i am not sure if it's a heat tube type... it has the black cover but that has a wire going into it, so does that mean it's electric? I actually brought it to a mechanic down the street from me and he said nobody there knew about carbs..... but he said it looked to him like a shitty choke....... so that's where i am at now.
It is electric. Disconect the wire. The choke should be wide open. If when the wire is off it's closed it's working backwards, I think. Connect the wire . Start the motor. If the engine is cold the choke should be closed. As the engine warms the choke should open. If you loosen the three little screws around the black plastic cap and turn it in the direction of the "Lean" arrow the choke should open some.
ok, so i got it running pretty good last night. thought i'd post to let anyone know that is having a similar problem. it was the choke for sure. i pulled off the choke thermostat to check it out and see if it was working backwards or anything. it was on "correctly" but it had way to much tension on the spring. meaning it had been spun on a few too many turns. or at least that is my hypothesis. so i took it off and then just placed it in the housing without turning the thermostat at all so it was just barely catching the choke lever and holding the choke closed. it started right up and i let it run for bit. then the big test would be to see if it would start hot, and it did. the choke layed slightly open on the second start and full open shortly after that. I drove it around for a bit and went to get gas but it wouldn't start after shutting it off at the pumps.....so i adjusted the choke to the lean setting a little more and voila, it started right up. drove it around some more and stopped at the store, came back out and it started right up again and has been starting fine since. so i guess that was the deal. seems so simple now and yet it was driving me crazy for the whole weekend. Thank you so much for all the help on this, i feel like i know way more about chokes and carbs after this, and that is a good feeling.
Question for you Rochester guys...I've been dealing with the same issue with my 235. HotRon, When you took off the choke thermostat cover was the thermo coil end somehow connected to the choke lever or was the coil end just sitting against the lever (i.e. nothing attaching both to each other)? Mine are not connected to each other and to me that doesn't make sense...when it heats up it will push the choke open, but when it cools nothing will be pulling the choke closed. Seems like I'm missing a clip on the end of the choke lever that connects it to the coil end. Is that the case or am I missing something? Or should the choke be normally held closed by some other missing piece? Thanks yall Nick
the end of the thermostat spring is just a loop on mine and it has one flat edge to the loop (if that makes sense), so the flat end just sits against the choke lever inside of the thermostat housing. it is not connected by anything, it just leans against it. i could be totoally wrong on this, but from what i've seen/figured out, it looks like the spring should hold the choke lever so that the choke is totally closed when off, so that when the spring is heated it expands and therefore looses tension and the choke lever will swing back with the expanding spring and allow the choke to open. again, i am not an expert and could be wrong here. but i did get mine working after this realization and setting it up to do that...
I'll give you some free advise. Carry a wooden clip in clothes pin with you. (the type with a spring) If your choke is sticking, you can clip that to the plate and keep it open. This works good on wet engines that want to flood because of a weak spark. And it being wood, it won't hurt anything, like jamming a screwdriver in there would.
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