Engine troubles! please help!

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lgarbz

lgarbz

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I have a 1974 Duster (3.7L Slant-6)
It had the engine rebuilt about 3 months ago.
Lately I have been having some bad problems with the engine stalling out.

Symptoms:
The alternator gauge on the dash starts tweaking out, and drops to almost -40.
The engine stutters and rumbles, as if it were running out of gas (even with full tank).
Often, the engine will stall out, and I will have to put it in park and restart it.
It only does it when I am not accellerating, when im breaking - at stop signs, lights, etc.
It is as if it is idleing VERY VERY low, so it decides to turn off.

I was told it could have something to do with the carburator/choke.
If you have any ideas what it could be, please post on this thread.
Thanks!
 
read service manual and set idle speed to the rpm noted for your year and model,i think it is 750 rpm,readjust idle mixtures to get the highest vacume reading then reset the idle rpm using s tach/dwell meter.the alternator may be tweaking because the engine isnt turning enough rpm for it to charge
 
How do you set the idle speed?
How do you change the idle mixture?
And how do you reset the idle rpm?
Thanks
 
Idle speed is a fine threaded screw on the carb, that rests against a stepped plate. Screw it in clockwise to raise the rpm.
Mixture screw is also on the carb, but location varies, depending on the carb.
Really, spend 10 bucks on a haines manual for you car, at the least, so you can see the pics, or google the name of you carb and look for images of it on the 'net.

At least by raising the idle speed a bit, you can make it more drivable, although it might not be correct.

good luck
 
Had the same thing happen with a '71 Scamp 6 cyl. It was a plugged breather cap. Pull the cap from the grommet on the valve cover and see what happens at idle. Good luck and keep us posted with any results.
 
Does the car have power brakes? could be a nasty vacuum leak at the booster.

Did you change anything? or is this a "one day it started doing this" type issue.
 
Get the books described in this thread as quickly as you can, to get up to speed on how your car is put together, how it's supposed to work, and how to fix it. Tune-up parts and technique suggestions in this thread. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.
 
Please clarify...when stopping, does the alternator go to full discharge and then the engine start to stumble? What happens when you first start the car...does it run okay when it's not in gear and idling?

If I'm understanding the symptoms correctly, it sounds like you have a serious electrical short that happens when you decelerate or hit the brakes, and is bad enough to deprive the engine of adequate voltage to keep running.

If it was a fuel problem that was causing the engine to stumble, the alternator needle shouldn't be reading negative if the engine was still running, and even if the engine dies, it shouldn't show a strong discharge unless every accessory was running.

Just curious...did you recently install a monster sound system?
 
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