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| Engine Dies When Warm https://slantsix.org/forum/viewtopic.php?t=59211 |
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| Author: | Nevada Scamp [ Tue Mar 01, 2016 12:37 pm ] |
| Post subject: | Engine Dies When Warm |
Hello, I am a new member here and this is my first post. I'm hoping someone here can help me with a problem. I have a 1973 Plymouth Scamp with a 225 and a Holley 1920 carb. I got the car about a year ago to have something to work on as a hobby. It is almost totally stock and has about 83,000 original miles. It sat in my neighbors yard for about 10 years before I purchased it from him, so one of the first things I did was to have the gas tank drained and I changed the fuel pump and filter. Then I did some basic maintenance (oil change, tune up, brakes, etc.) and it seemed to run good for several months. It doesn't leak or burn any oil. It passed the Nevada smog check and I registered it and started driving it on weekends. It always ran fine except for the choke wouldn't disengage properly, so I changed the vacuum pull-off the other weekend. Low and behold, the choke works great now! However, now I have a new problem! After I drive the car for about 10 minutes, it dies. The carb seems to be getting gas, but it will not start. However, if I wait a few hours and let the engine cool down. It fires right up. I can't see how replacing the choke pull off would have caused this, unless I messed up the float vent linkage somehow. Is there a short list of things I should check before proceeding? I do notice that the charging gauge goes way past 40 when I rev the engine and at night the lights are very dim at idle. Should I have the alternator bench tested? I am trying to figure out where to start to address this issue. Any help would be appreciated. |
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| Author: | Reed [ Tue Mar 01, 2016 12:45 pm ] |
| Post subject: | |
Hello and welcome! From the symptoms it sounds like the choke was staying partially "on" or closed before you replaced the vacuum pulloff. This might have caused a previous owner to set the curb idle mixture too lean since the carb woudl appear to be running rich if the choke as partially closed. Now that the choke opens fully the idle mixture might be too lean. Try turning the idle mixture screw out 2 1/2 turns and see if the engine will run. If it does, you will need to go through the process of resetting the curb idle mixture and speed. It is also possible tha there is a vacuum leak somewhere, but I would start with the idle mixture setting. |
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| Author: | Nevada Scamp [ Tue Mar 01, 2016 6:55 pm ] |
| Post subject: | |
Thanks for the info. I will check the curb idle adjustment this weekend and see if that cures the problem. |
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| Author: | wjajr [ Wed Mar 02, 2016 5:40 am ] |
| Post subject: | |
Reed: Quote: Try turning the idle mixture screw out 2 1/2 turns and see if the engine will run.
I think Reed meant to say was; gently turn in idle mixture screws in until just seated (over tightening will damage screw), and than back out 2 1/2 turns). This is idle mixture's base setting, and screw may need to be tweaked in or out for optimal idle performance. If you find that there is no discernible change in idle quality at or around 2 1/2 turns, and three or four turns are needed, than there most likely is a vacuum leak introducing additional air causing a leaning of idle mixture. Charging problems should be taken up on "Electrical Page" for an in depth explanation, and methods to correct your problem. That said; one common cause of over charge is voltage drop within the harness. For every volt lost from bad conductors, poor corroded connections both in ground path and positive side of circuit will cause voltage regulator to increase alternator out put to battery by one volt. Another over charge cause is a battery that won't or can't accept a charge because it is too old or defective in some way. A little detective work with a volt ohm meter (VOM) will locate most voltage drop problem areas. Collecting up alternator, voltage regulator, battery for bench testing at a competent auto parts store, or automotive electrical shop will find any problems with those three pieces of equipment before one starts changing out parts willy-nilly. |
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