Engine suddenly runs rough under load
10-03-2005, 08:34 AM
#1
Melting Slicks
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Location: New Milford CT
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Engine suddenly runs rough under load
1957 283 220hp Powerglide, all stock, restored 20 years ago, engine not touched until now.
Changed the spark plugs to stock R45S. Old ones(R46S) looked pretty good. Car started quicker, ran real smooth, accelerated stronger. Drove 20 miles to the cruise nite, then drove back, ran perfect.
Started it up next day, it started fine but it stumbled and ran rough for about 10 or 20 seconds, and backfired through the carb if I give it any gas.I let it warm up completely. While driving it does the run rough, stumble thing again. Also it backfired through the carb. Under the slightest load (1/4 throttle)it wants to die. It can only be driven with a feather light throttle foot.
I rechecked the new plugs, wires, connections, timing and reset the used points, choke is open all the way.
I suppose maybe the carb floats are sticking ( but the fuel filter is full and clean) or the points, coil or condenser is bad or? Where to start?
Changed the spark plugs to stock R45S. Old ones(R46S) looked pretty good. Car started quicker, ran real smooth, accelerated stronger. Drove 20 miles to the cruise nite, then drove back, ran perfect.
Started it up next day, it started fine but it stumbled and ran rough for about 10 or 20 seconds, and backfired through the carb if I give it any gas.I let it warm up completely. While driving it does the run rough, stumble thing again. Also it backfired through the carb. Under the slightest load (1/4 throttle)it wants to die. It can only be driven with a feather light throttle foot.
I rechecked the new plugs, wires, connections, timing and reset the used points, choke is open all the way.
I suppose maybe the carb floats are sticking ( but the fuel filter is full and clean) or the points, coil or condenser is bad or? Where to start?
10-03-2005, 10:28 AM
#2
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Location: Greenville, Indiana
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the points, coil or condenser is bad or? Where to start?
I think you're in the ball park. Also, check your primary coil voltage or run a hot wire straight to the coil and see how it runs.
I think you're in the ball park. Also, check your primary coil voltage or run a hot wire straight to the coil and see how it runs.
10-03-2005, 10:42 AM
#3
Melting Slicks
I would change the coil immediately. It sounds like it is breaking down under power. Mine did the same thing several months ago. After working on everything else I finally changed the coil (which was 4 weeks old) and the problem was solved.
Roy
Roy
