mat in tn Posted January 25, 2022 Share Posted January 25, 2022 His signature says 460. And the 351HO and 460 both used the 4180C, although jetted differently. Strange that I can't get in. I wonder just how much the AutoZone supplied carbs will be "jetted differently, if at all? but it seemed to be a fairly reasonable price either way for a replacement. Link to comment Share on other sites More sharing options...
Bullnose Gator Posted January 25, 2022 Author Share Posted January 25, 2022 I wonder just how much the AutoZone supplied carbs will be "jetted differently, if at all? but it seemed to be a fairly reasonable price either way for a replacement. yeah, it's a 460. What does jetted differently mean, and if it is, would that cause it to not work or just not work as well as the original? Link to comment Share on other sites More sharing options...
rcarlisle Posted January 25, 2022 Share Posted January 25, 2022 yeah, it's a 460. What does jetted differently mean, and if it is, would that cause it to not work or just not work as well as the original? Do you have a vacuum gauge? I just got one and it seems pretty invaluable for figuring things out. It was like $15 at Harbor Freight, comes with a lot of stuff and it's own case. I'm really interested in knowing the final outcome on this one, since I've been having fueling issues lately. Turns out mine is a screw going missing I think. Link to comment Share on other sites More sharing options...
mat in tn Posted January 25, 2022 Share Posted January 25, 2022 Do you have a vacuum gauge? I just got one and it seems pretty invaluable for figuring things out. It was like $15 at Harbor Freight, comes with a lot of stuff and it's own case. I'm really interested in knowing the final outcome on this one, since I've been having fueling issues lately. Turns out mine is a screw going missing I think. trying to explain how a carb works can be awkward because you don't know the knowledge of the person(s) listening. the fuel which the engine burns is actually fuel vapor. liquid does not burn. that fuel vapor is added to oxygen rich air. it's the oxygen which feeds the burn of the fuel. the carb holds liquid gasoline in a reservoir with a tiny "straw" type passage leading to the air venturi. the "barrel" which has a slight hourglass restriction causing a vacuum and drawing gas vapor through the straw into the air stream. the jetting is a finer method of tuning the straw to make sure the carb gets the proper ratio of fuel to air in a range of run conditions. heavy load will require a little more fuel vs a lighter load needing less. this is a basic explanation of the main circuit. the idle circuit is another finer set metering circuit which is semi-independent of the main venturi. cubic inches of the engine play a big part of course but it is the air fuel mixture set for the expected demand that comes first. too much fuel is not only expensive and wasteful, but it is bad or worse than not enough for the engine a good example of this might be the 300ci six with a 1 barrel of approx. 269 cfm while the 302 ci came with a 600 cfm 4barrel both works well for their respective demands. I hope I gave the engineers a good laugh with my simplification. Link to comment Share on other sites More sharing options...
Bullnose Gator Posted January 25, 2022 Author Share Posted January 25, 2022 Do you have a vacuum gauge? I just got one and it seems pretty invaluable for figuring things out. It was like $15 at Harbor Freight, comes with a lot of stuff and it's own case. I'm really interested in knowing the final outcome on this one, since I've been having fueling issues lately. Turns out mine is a screw going missing I think. Man, this has been quite the head scratcher from the start. I know it has been greatly complicated by how little I know, therefore, troubleshooting has been more like shots in the dark. But with the knowledge I have picked up coupled with regular logic, it still doesn't seem to be following the expected norms for these symptoms. Which brings me to ANOTHER development this morning. I ordered the carb last night, but it won't be here for a week and I just can't help but keep tinkering in the mean time. So I circled back through the front and rear fuel bowls again to start. The rear bowl seemed to be the problem based on fuel coming out of the fuel bowl vent, but I had previously adjusted the rear needle and seat down pretty far and that didn't fix it. So this morning I adjusted it up quite a bit and then back down to about as far down as it could go using the nut. I cranked it up and...that seems to have fixed the problem. I checked the sight plug and the fuel is right where it should be. I won't know for sure until I replace the front fuel bowl cover gasket because it is leaking too bad to let it run for more than a couple of minutes. So my new questions are: 1) If that was the problem, does that mean the float was sticking since it didn't seem to respond to my first adjustments? 2) If so, should I expect it to stick again in the future and should I replace the float? Link to comment Share on other sites More sharing options...
Bullnose Gator Posted January 25, 2022 Author Share Posted January 25, 2022 trying to explain how a carb works can be awkward because you don't know the knowledge of the person(s) listening. the fuel which the engine burns is actually fuel vapor. liquid does not burn. that fuel vapor is added to oxygen rich air. it's the oxygen which feeds the burn of the fuel. the carb holds liquid gasoline in a reservoir with a tiny "straw" type passage leading to the air venturi. the "barrel" which has a slight hourglass restriction causing a vacuum and drawing gas vapor through the straw into the air stream. the jetting is a finer method of tuning the straw to make sure the carb gets the proper ratio of fuel to air in a range of run conditions. heavy load will require a little more fuel vs a lighter load needing less. this is a basic explanation of the main circuit. the idle circuit is another finer set metering circuit which is semi-independent of the main venturi. cubic inches of the engine play a big part of course but it is the air fuel mixture set for the expected demand that comes first. too much fuel is not only expensive and wasteful, but it is bad or worse than not enough for the engine a good example of this might be the 300ci six with a 1 barrel of approx. 269 cfm while the 302 ci came with a 600 cfm 4barrel both works well for their respective demands. I hope I gave the engineers a good laugh with my simplification. Valiant effort, Mat lol. Some of it was still not simple enough for this listener, but your description did explain the jetting mechanics in a way I could understand, thanks. Link to comment Share on other sites More sharing options...
rcarlisle Posted January 25, 2022 Share Posted January 25, 2022 trying to explain how a carb works can be awkward because you don't know the knowledge of the person(s) listening. the fuel which the engine burns is actually fuel vapor. liquid does not burn. that fuel vapor is added to oxygen rich air. it's the oxygen which feeds the burn of the fuel. the carb holds liquid gasoline in a reservoir with a tiny "straw" type passage leading to the air venturi. the "barrel" which has a slight hourglass restriction causing a vacuum and drawing gas vapor through the straw into the air stream. the jetting is a finer method of tuning the straw to make sure the carb gets the proper ratio of fuel to air in a range of run conditions. heavy load will require a little more fuel vs a lighter load needing less. this is a basic explanation of the main circuit. the idle circuit is another finer set metering circuit which is semi-independent of the main venturi. cubic inches of the engine play a big part of course but it is the air fuel mixture set for the expected demand that comes first. too much fuel is not only expensive and wasteful, but it is bad or worse than not enough for the engine a good example of this might be the 300ci six with a 1 barrel of approx. 269 cfm while the 302 ci came with a 600 cfm 4barrel both works well for their respective demands. I hope I gave the engineers a good laugh with my simplification. EXCELLENT explanation! I'm in the middle and that made good sense. AND it helped the OP understand better. I have spent a lot of time reading, but also by studying a carb and passages by actually holding one in my grubby hands. Link to comment Share on other sites More sharing options...
mat in tn Posted January 25, 2022 Share Posted January 25, 2022 trying to explain how a carb works can be awkward because you don't know the knowledge of the person(s) listening. the fuel which the engine burns is actually fuel vapor. liquid does not burn. that fuel vapor is added to oxygen rich air. it's the oxygen which feeds the burn of the fuel. the carb holds liquid gasoline in a reservoir with a tiny "straw" type passage leading to the air venturi. the "barrel" which has a slight hourglass restriction causing a vacuum and drawing gas vapor through the straw into the air stream. the jetting is a finer method of tuning the straw to make sure the carb gets the proper ratio of fuel to air in a range of run conditions. heavy load will require a little more fuel vs a lighter load needing less. this is a basic explanation of the main circuit. the idle circuit is another finer set metering circuit which is semi-independent of the main venturi. cubic inches of the engine play a big part of course but it is the air fuel mixture set for the expected demand that comes first. too much fuel is not only expensive and wasteful, but it is bad or worse than not enough for the engine a good example of this might be the 300ci six with a 1 barrel of approx. 269 cfm while the 302 ci came with a 600 cfm 4barrel both works well for their respective demands. I hope I gave the engineers a good laugh with my simplification. EXCELLENT explanation! I'm in the middle and that made good sense. AND it helped the OP understand better. I have spent a lot of time reading, but also by studying a carb and passages by actually holding one in my grubby hands. I guess the only real answer to whether it will stick again is maybe. I always have to ask "how long did this truck sit"? liquid gas can be a fair solvent for a while but then it can get gummy when talking about the fine passages in a carburetor. the inlet valve was disturbed by you going through the range of adjustment so it could be that simple. the rear bowl does not get the turnover in fuel which the front does for most people. I myself seem to flush out the old fuel more than most. Haha. The factory4 barrel runs on the front (primary). as if it were only a two barrel unless you stick your foot in it enough to allow the vacuum of the engine to open the secondary when it needs it. you give it permission and it regulates itself. Link to comment Share on other sites More sharing options...
Bullnose Gator Posted January 26, 2022 Author Share Posted January 26, 2022 I guess the only real answer to whether it will stick again is maybe. I always have to ask "how long did this truck sit"? liquid gas can be a fair solvent for a while but then it can get gummy when talking about the fine passages in a carburetor. the inlet valve was disturbed by you going through the range of adjustment so it could be that simple. the rear bowl does not get the turnover in fuel which the front does for most people. I myself seem to flush out the old fuel more than most. Haha. The factory4 barrel runs on the front (primary). as if it were only a two barrel unless you stick your foot in it enough to allow the vacuum of the engine to open the secondary when it needs it. you give it permission and it regulates itself. I replaced the front fuel bowl gasket tonight and took her for a spin. Sure enough, the rear bowl float level was the problem after all. There were a few hesitations as I got it up to 45mph+, but they didn't last and I assume it was her working out the cobwebs after sitting for over two months waiting on me to figure this out. All it took was for me to order a new carb in order to figure it out lol. So I'm quite happy, and a little embarrassed that it took 4 pages of me bothering yall for months, but thanks for all the help! Link to comment Share on other sites More sharing options...
mat in tn Posted January 26, 2022 Share Posted January 26, 2022 I replaced the front fuel bowl gasket tonight and took her for a spin. Sure enough, the rear bowl float level was the problem after all. There were a few hesitations as I got it up to 45mph+, but they didn't last and I assume it was her working out the cobwebs after sitting for over two months waiting on me to figure this out. All it took was for me to order a new carb in order to figure it out lol. So I'm quite happy, and a little embarrassed that it took 4 pages of me bothering yall for months, but thanks for all the help! to the best of my knowledge, this is exactly why Gary started this. I found help and hopefully i have been helpful in return. Link to comment Share on other sites More sharing options...
Recommended Posts