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Poor acceleration when hot

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AustinJim

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I have a 78 Spitfire with a ZS carb. After driving it for 20 minutes or so (with ambient temp around 70) the car begins to sputter and hesitate when accelerating. This happens from a stop and when accellerating while already driving. I think the car is running rich and I will adjust that as soon as I can find someone local with the tool but I'm not sure that would cause this problem. Any hints on what to check?
Thanks!
 
Jim, sometimes when you push your choke cable in the chokes on the carb will not completly shut which would cause a rich condition when hot, make sure your cable is working freely and not hanging up at the carb end of it. othere than that you may need a carb adjustment or rebuild.
 
This car as the automatic water choke so no cable problem. One thing I did check a while back was the throttle bushings. I sprayed starter fluid on the outside of the carb where the throttle rod comes out and the engine sputtered. I'm pretty sure this indicates the busings and/or shaft are worn. Could the sputtering when hot be caused by work bushings/shaft?
 
That could be causing a miss or stumble from a vacume leak around the throttle shafts, but that would give you more of a lean conditon instead of rich, with a rich condition it is starting to sound more like a worn needle and seat/and you might have worn shaft bushings also. If this is the case it sounds like your ready for a carb rebuild.
 
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I...After driving it for 20 minutes or so (with ambient temp around 70) the car begins to sputter and hesitate when accelerating. This happens from a stop and when accellerating while already driving. I think the car is running rich and I will adjust that as soon as I can find someone local with the tool...

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Bear in mind that many 'carb' problems are resolved only after working on the ignition system. In your case I would suspact the coil or condensor as both may suffer with heat.
 
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