5 Star Rising Posted November 24, 2009 Share Posted November 24, 2009 Picked up 73 240 project in decent shape. It hasnt run for 20 years. Everything on this car is all bone stock but deteriorated. After going through alot of stuff including dropping the gas tank/ hot tanking and relining it. I found my carbs were completely plugged up. A buddy of mine had a set of flat tops that had been rebuilt about 5 years back and ran good when they were pulled off a car 2 years ago. I put them on and got the car running. Only one of the carbs has the glue missing so you can adjust the screw at the bottom. Any how the car runs rough and a bit rich. Also when you try to start the car for the first time of the day you need to spray starting fluid in both carbs a few times to get it going, then you can start the car and it will run on its own. Any one have any experience with these flat top pieces of crap? I know these carbs suck, but I want to keep this Z all stock.. I have 3 other Z's including a 73 240 V8 conversion race car lol.. Also I put a new electric fuel pump in this car and got rid of the mechanical pump as it was toast as well. But now I might have a vapor lock problem cause I gotta use starting fluid everytime WTF lol.. Rob Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 24, 2009 Share Posted November 24, 2009 Glue? Jet adjustment is internal on the 73 carbs as well as 74... what is the glue you speak of? If it runs rich, make surethe power vavle is working correctly. Your attitude no doubt affects how the car runs, revise it and likely things will get better (Reference material: Buddy Hackett in Herbie the Love Bug series...) Quote Link to comment Share on other sites More sharing options...
5 Star Rising Posted November 25, 2009 Author Share Posted November 25, 2009 Well I dont have a manual on this car and usaully I have had all 280zs in the past. But on both sides on the lower carbs (facing the radiator) there is a hole. On the 4 carbs I have 3 of them have a glob of factory glue that was put over the hole to maintain factory settings. On one of my carbs (firewall carb) some one had removed the glob of glue exposing a copper jet adjusting screw. If you play with this scew it seems to effect the way the car runs. Are you saying there is another air/fuel mixture adjust interenally in these fine pieces of work? Rob Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 25, 2009 Share Posted November 25, 2009 ? I don't have the manual in front of me, but can't for the life of me figure out what you are adjusting. There is a large screw on the front carb which will adjust fuel mix for idle speed, and works in conjunction with the volume screw on the balance tube. They are not small, globbed in glue, or copper colored. Whatever they exposed, it's screwing up the works. The Factory Service Manual is available online, take a gander at it and see if you can get a reference for the screw that I can figure out. I don't know what screw they exposed, but it's one you don't mess with. The front carb controls fuel mix for both carbs at idle. The carbs off-idle mix is an internal set adjustment accessed by removing the float bowl, and is far richer than the normal SU setup, normally it needs no adjustment as all engine speeds up to 1500-2000 can be handled by the idle circuit alone. When they run rich, the power valve (like on a Holley) is usually shot from a backfire or something. The copper screw is a mystery to me. A celphone photo is worth a thousand words... Quote Link to comment Share on other sites More sharing options...
blue72 Posted November 26, 2009 Share Posted November 26, 2009 xenonS30.com is your friend. The FSM is available there for download. Quote Link to comment Share on other sites More sharing options...
5 Star Rising Posted November 26, 2009 Author Share Posted November 26, 2009 Well I will see if I can dig up a manual, or check it out on the web. So the front carb big screw controls air/fuel mixture on Both carbs at idle? ? I don't have the manual in front of me, but can't for the life of me figure out what you are adjusting. There is a large screw on the front carb which will adjust fuel mix for idle speed, and works in conjunction with the volume screw on the balance tube. They are not small, globbed in glue, or copper colored. Whatever they exposed, it's screwing up the works. The Factory Service Manual is available online, take a gander at it and see if you can get a reference for the screw that I can figure out. I don't know what screw they exposed, but it's one you don't mess with. The front carb controls fuel mix for both carbs at idle. The carbs off-idle mix is an internal set adjustment accessed by removing the float bowl, and is far richer than the normal SU setup, normally it needs no adjustment as all engine speeds up to 1500-2000 can be handled by the idle circuit alone. When they run rich, the power valve (like on a Holley) is usually shot from a backfire or something. The copper screw is a mystery to me. A celphone photo is worth a thousand words... Quote Link to comment Share on other sites More sharing options...
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