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By YellowWing - 15 Years Ago
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I know many on the board replace their teapot carbs with something newer. For those that don't here is problem I'm having with mine that may help you in the future. My 56 with a 312 starts and idles fine hot or cold. It runs fine up to about 1/2 to 2/3 throttle, above that I get a smell of fuel in the cabin and the engine starts surging. I wasn't going to look for the problem as the engine is coming out in a couple weeks for new carb, ignition, heads, intake , cam, etc. However as the temperature around here has gotten warmer the surging has gotten worse and I thought I would check a few simple things to get me through. Checked plugs, on the dark side not unexpected with the symptoms. Timing 10 degrees with no vac 19 with. Decided to check the float level. After running the engine for 30 seconds or so I removed the top of the float chamber and checked the level. Fuel was 3/4 inch below top of bowl (should be 1/2 inch) but fuel was still entering bowl. This continued for 5 min or so. I first thought I had a bad needle or seat but discovered the fuel was not coming from inside the seat but from around it. I have since pulled the carb and found that fuel is leaking past the small fiber washer that seals the seat to the carb body. I will take the carb to work tomorrow and see what I can do to repair. I don't know if this is the cause of my problem but will post about the repair and if it helps after I finish. Mike
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By oldcarmark - 15 Years Ago
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Hey Mike! That is about the most comon complaint about these carbs.I remember reading somewhere on this site that there is a better replacement available to repair that.I had the same trouble with mine and in the end switched to the new Holley 390.Hoosier is very knowledgeable about these carbs.Hopefully he will see your post.
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By Ted - 15 Years Ago
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Screw in or spring loaded needle seat on the Teapot? The screw in needle seat design uses a fibre gasket while the spring loaded needle seat design uses an O ring.
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By YellowWing - 15 Years Ago
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Ted, it has a spring loaded seat but a fiber gasket. I was already thinking of installing an o ring, now I know that is what it was supposed to have. Thanks for the help. I will post the results of the surging problem.
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By Ted - 15 Years Ago
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Be sure to use some white grease or Vasoline on the rubber O ring during the installation process.
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By YellowWing - 15 Years Ago
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I always do, thanks again Ted. Mike
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By DANIEL TINDER - 15 Years Ago
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"Spring loaded seat"? Didn't know there was one. Details?
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By YellowWing - 15 Years Ago
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Daniel, seat drops into the carb body, a spring rests on top of it then you screw a threaded cover on that presses on the spring holding the seat in place. I installed a o ring today and the seat no longer leaks. Just need to install the carb and see how it works. Mike
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By marvh - 15 Years Ago
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Those type of non-threaded seats are now not included in the new carb kits. It says re-use your old ones with the new needle valve. That is fine if the seat is in good condition.
I have changed up many of those spring loaded type of seats to the threaded type by threading the float bowl to accept the threaded seat. The threaded seat is 24 TPI however is much larger than the 3/8" diameter fine thread bolt.
I found the tap for installing 24 TPI (3/8 SAE bolt) heli-coil coils is same OD as the seat threads are. I just start the tap nice and straight so have a clean thread than replace the old spring loaded seat with the newer threaded seat.
On a disclaimer: Before using a heli-coil tap I would try it in a piece of metal to do a test thread as maybe some heli-coil taps are different sizes than the one I have. I would not want someone to ruin their float bowl by a mistake.
marv
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By YellowWing - 15 Years Ago
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Reinstalled the carb today, big improvement! Engine much smoother and no more smell of gas. Still cuts out at higher throttle settings but better. Seems more like an ignition problem. I can live with it till I pull the engine in a couple weeks to perform the upgrades. thanks for the help guys  Mike
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By pegleg - 15 Years Ago
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Mike, Check your float height, and maybe fuel pressure also. Either issue will contribute to the high throttle setting miss.
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By YellowWing - 15 Years Ago
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Frank, I checked the float height but didn't bother with pressure as pump and carb will both be replaced in a couple weeks. Just figured this thread might help others with similar problems. Thanks, Mike
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By pegleg - 15 Years Ago
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Fair enough. Ted nailed the issue anyhow, as usual!!
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