BigBrother-84 Posted January 8, 2023 Share Posted January 8, 2023 Hi Gentlemen! Some of you already know that I am trying to obtain better cold start with Big Brother. Last summer I changed the old Holley 4180-C (that came with a replacement 351W 4V engine, around 2010). Installed a universal Holley carb, model 4160-C 600 Polished. I realized today that the choke flap is never fully closed, contrarily to the old 4180-C: Winter here can be cold... very cold. I am wondering if this "never tightly closed" choke flap can result in a too lean mixture for cold starts? If so, is there replacement flaps available that will completely close the intake? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 8, 2023 Share Posted January 8, 2023 Would you look at that!?! Holley clipped the flap and did away with staked attachment screws. They also brought back adjustable float valves! And they still call this an 0-80457 but I'm not sure of the suffix. I don't think this should effect starting Jeff. The vacuum pull-off would crack open the choke plate in any case. Holley probably did this to head off warranty claims. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 8, 2023 Share Posted January 8, 2023 Would you look at that!?! Holley clipped the flap and did away with staked attachment screws. They also brought back adjustable float valves! And they still call this an 0-80457 but I'm not sure of the suffix. I don't think this should effect starting Jeff. The vacuum pull-off would crack open the choke plate in any case. Holley probably did this to head off warranty claims. Interesting! But I agree - don't worry about it if the engine starts well, and I bet it will. Can't imagine Holley would do something that would cause starting problems. Link to comment Share on other sites More sharing options...
Rembrant Posted January 9, 2023 Share Posted January 9, 2023 Interesting. I bought a new 600CFM 4160 a few years ago and didn't notice this, but when I go back and look at the pics, it had the same choke plate. I bought that carb brand new in 2017 or 2018. Link to comment Share on other sites More sharing options...
AmericanSavage Posted January 9, 2023 Share Posted January 9, 2023 Interesting. I bought a new 600CFM 4160 a few years ago and didn't notice this, but when I go back and look at the pics, it had the same choke plate. I bought that carb brand new in 2017 or 2018. https://forum.garysgaragemahal.com/file/n129696/4160.jpg That's nice. I have a 500cfm manual choke on mine. I would say more, but I do not want to test Gary's patience. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 9, 2023 Share Posted January 9, 2023 Interesting. I bought a new 600CFM 4160 a few years ago and didn't notice this, but when I go back and look at the pics, it had the same choke plate. I bought that carb brand new in 2017 or 2018. https://forum.garysgaragemahal.com/file/n129696/4160.jpg That's nice. I have a 500cfm manual choke on mine. I would say more, but I do not want to test Gary's patience. Gary's fine, go for it. Link to comment Share on other sites More sharing options...
86 12 Brutus Posted January 10, 2023 Share Posted January 10, 2023 Gary's fine, go for it. I dont think the choke plate is supposed to fully close. I just got my 4160 yesterday from a friend, and its choke plates do not fully close. On the 2150 that the 4160 is going to replace, that one does. I didn't realize this until a few weeks ago. We started the engine and it was running very rough and then it killed. We did the usual procedures when it wouldn't start back up again. check fuel, check spark, scratch head, repeat, cuss and scratch head some more. It was nick who noticed it, he hollered out, George, crank it, i did and it started right up. Turns out the choke plate was completely closed, we just didn't see it, it was cold out, i saw the choke plate closed which it was supposed to, just didnt realize it was all the way shut. Could't really say why this happened. It happened a few more times, but by this time is when we realized it was time for a new carb and intake so i just left it alone. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 10, 2023 Share Posted January 10, 2023 I dont think the choke plate is supposed to fully close. I just got my 4160 yesterday from a friend, and its choke plates do not fully close. On the 2150 that the 4160 is going to replace, that one does. I didn't realize this until a few weeks ago. We started the engine and it was running very rough and then it killed. We did the usual procedures when it wouldn't start back up again. check fuel, check spark, scratch head, repeat, cuss and scratch head some more. It was nick who noticed it, he hollered out, George, crank it, i did and it started right up. Turns out the choke plate was completely closed, we just didn't see it, it was cold out, i saw the choke plate closed which it was supposed to, just didnt realize it was all the way shut. Could't really say why this happened. It happened a few more times, but by this time is when we realized it was time for a new carb and intake so i just left it alone. Typically a choke plate shouldn't completely close. There are specs for each application, but something like 1/16" is a good starting point when you have a new-to-you carb. But you have to be somewhat careful setting the choke as there is slop in the linkage and the choke plate is offset on its shaft. So the vacuum of the engine turning over will take the slop out and open the choke plate a bit and now you may not have the same setting you had before. My approach when I set a choke is to take the slop out when dialing in the initial 1/16". So it may look like the choke is fully closed if the slop allows the choke to move that far, but when the engine cranks it'll open to spec. Link to comment Share on other sites More sharing options...
BigBrother-84 Posted January 10, 2023 Author Share Posted January 10, 2023 Typically a choke plate shouldn't completely close. There are specs for each application, but something like 1/16" is a good starting point when you have a new-to-you carb. But you have to be somewhat careful setting the choke as there is slop in the linkage and the choke plate is offset on its shaft. So the vacuum of the engine turning over will take the slop out and open the choke plate a bit and now you may not have the same setting you had before. My approach when I set a choke is to take the slop out when dialing in the initial 1/16". So it may look like the choke is fully closed if the slop allows the choke to move that far, but when the engine cranks it'll open to spec. Gary, when I discovered this "cut plate" on my new carb, I thought about this little opening gap required when adjusting a "normal" carb, and was wondering if Holley made this "cut plate" to avoid owners to have to deal with, and simply have a full closing flap. And potentially drop a 1/16" drill bit in the intake while adjusting... More seriously, I find this cut much wider than the usual 1/16" opening. That's why I was wondering about a too lean mixture on very cold start conditions. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 10, 2023 Share Posted January 10, 2023 Gary, when I discovered this "cut plate" on my new carb, I thought about this little opening gap required when adjusting a "normal" carb, and was wondering if Holley made this "cut plate" to avoid owners to have to deal with, and simply have a full closing flap. And potentially drop a 1/16" drill bit in the intake while adjusting... More seriously, I find this cut much wider than the usual 1/16" opening. That's why I was wondering about a too lean mixture on very cold start conditions. Jeff - I don’t know what to think about the extra slots. But the proof is in the pudding, meaning let’s see how the truck starts. You can always dial in another notch or two if you think you need more. Link to comment Share on other sites More sharing options...
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