Carburetor Central
If you have questions about the SU Carburetors, this is where you can find the answers.
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New to the forum and already feel welcome, thank you for that. Anyways, thanks to a suggestion Zed Head, I was able to hear my 240z sputter up for time last night. Unfortunatly, it won't stay running for more than 30 seconds. The guy I bought it from said it was running good when he parked it, but then he tried to adjust the carbs and screwed them up. It sputters up after cranking for 10 seconds, and within 15 seconds fuel is pissing from the float intake hose, and soon after starts pissing out of the carburator air horn as the engine misses, backfires, and dies. What am I missing? I can already tell this forum is a plethora of information so if there is a …
Last reply by siteunseen, -
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Ztherapy refurbished both of my 3 sscrews roundtop SU Carbs and install Brand new SM Needles on them. My car engine is not stock it has been upgraded to 2.6 L with oversized pistons and a Shneider 274F Camshaft. Should i consider changing the needles to another type to get a better performance at idle?
Last reply by jalexquijano, -
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I am having a heck of a time getting the correct air/fuel mixture set on my carbs. I have a 260z and the engine was just rebuilt with .020" over pistons, stage 2 cam from MSA and 3-2 MSA header. I am running the stock 260 intake/balance tube with emissions removed and 4 screw round top SU's. I also just rebuilt the carbs with the ztherapy kit. The problem I am having is at idle the wideband is reading an air/fuel ratio around 13 and at part throttle, it really leans out at around 14.5 - 15.5. I am pretty sure the needles are n27's and was wondering if I need to switch to SM needles? I have followed pretty much every guide to tuning that I could find on here but I can stil…
Last reply by 240260280, -
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while tuning my 3 screws round top su carbs this weekend after setting the timing to 14 btdc, i found out that even if i turn the fuel mixture knob 5 turns clockwise when i raise the piston the engine shuts down. Could the float level in this rear carb be wrong? It does not happen on the front carb. My tuning procedure starts at 2.5 turns clockwise (lowering the jet 2.5 turns). After that i set the idle rpm at 1000 RPM and doublé check the air with the synchometer. Then i turn the fast idle screw until it hits 3000 RPM on the tachometer and verify the balance amongst both carbs with the synchometer. i tend to increase the fuel mixture knob to 3 turns each depending o…
Last reply by jalexquijano, -
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So I wanted to join ZONC.org. Went to the web page, got a membership, sent $30 via PAYPAL and it only wanted the year of my car and the month of my birthday. I thought Hmm, Thats different! Maybe they will finish the registration later on... NO! Did I just get screwed? Polecat
Last reply by 240260280, -
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Alrighty. I've replaced three mechanical fuel pumps in my 73 240z in the past five months. [Because I initially thought this was the root of all of my problems] It seems as though the pump loses it's prime every time she sits for a week or two. For example, today: oem-spec fuel filter is clean and new. The filter is full of gas. Car will not start with a solid 2 minutes of cranking. No fuel is making it to carbs. What gives? It's like the pump is sitting there doing nothing. I can blow gas through and suck gas in from the supply line easily. Gas tank is fairly clean--fuel filters have never been dirty in the past 6 years of ownership. SU floats have b…
Last reply by siteunseen, -
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Hello, Finally got some time to try to get the Z running. I have the original 3 screws that came on it rebuilt with Ztherepy kits. Got It to start fine and run without the choke after a little warming up. Idles at about 750 to 800. Started to adjust and balance the carbs and realized the rear carb isn't working. I can screw the mixture dial all the way out or in tight and there is no change at all. If I cover the carb with my hand or lift the piston nothing changes. The front carb adjustment works the way it should. I have set the float with the 10 turns down method and verified that the fuel is flowing to that level and stopping at the right height. But cant figure …
Last reply by jeanp, -
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Last night while fine tuning my round top 3 screws mixture adjusting nuts to mantain a correct idle while preventing the spark plugs getting carbón fouled due to rich mixture, i discovered that my car is taking 5 to 7 minutes to warm up and i need to drive it with the choke pulled until the temperature at the temp gauge reaches to 1/2. Otherwise, if i remove the choke, the acceleration is very poor and tends to fail. As part of the history of this car, i did remove the inline heat control thermostat and plugged the coolant lines on the back of both carburetors to lower the percolation. In view of this, i have the following questions: 1. I live on a Tropical warm wea…
Last reply by kully 560, -
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Just bought a 72 240z, I need help in a bad way Sent from my iPhone using Classic Zcar Club mobile
Last reply by esmit208, -
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Background: When I got the car, it was a stock L26 with flat top carburetors. Three years ago, I changed out the carburetors for round top carburetors. For a while I noticed that after I had been running at freeway speeds, returning to stop-and-go traffic would result in hesitation during acceleration until it seemed like the car cooled down for a while. I enriched carburetors some more, and the problem seemed to go away. In February, I did an engine swap, putting in an L28 with an N47 Maxima head. Since the head wasn't configured for a mechanical fuel pump, I just ran the stock electric fuel pump. The hesitation returned, even with enriching the carburetors eve…
Last reply by SteveJ, -
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I don't know much about how these work but if you had hot fuel in the immediate area of the carbs could you pull the choke, dropping the nozzles away from the needle and push the hot fuel through the return with an electric fuel pump? Sorta like purging an nos system?
Last reply by siteunseen, -
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Thinking of replacing my clear fuel filter with a Malpassi King Fuel Filter which comes with a pressure regulator. Which one should i purchase for my 240z?? 85mm, 8mm outlet tails or 67mm? http://www.ebay.com/itm/Malpassi-Filter-King-Fuel-Pressure-Regulator-and-Gauge-clear-glass-bowl-/110622432307
Last reply by RS02,
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Wilbur
