03-19-2018, 10:19 AM | #1 |
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69 Chevy 250 motor
Help! After reading multiple threads I can not fix my problem. I have a 69 Chevy C20 with the 4.1 L 250 with a Rochester monojet Gm.
Issue is every time I shift and put the motor under load at low rpms the motor spits and stumbles just for a second. Here’s alittle back ground. Coil replaced with MSD baster2 and ballast resistor New spark plugs and wires Installed a fuel filter Cleaned out carb mainly just the float bowl New distributor cap and rotor Here’s how it began Last week my truck died on the side of the road so I got looking under the hood and found the wire off the starter cilinoid to be melted and split apart( wire went to dash and coil) so I did a bush fix and got her home and completely replaced the wire. All running good at this point. A few days later I installed a fuel filter before the pump. All was good until I found the fuell gauge stuck at the 3 o’clock position. Fixed that now back to square 1. So I proceeded to install a new coil plugs and wires along with cap and rotor motor now running a lot better. BUT found a wire smoking at the plug as it enters the dash so I found I needed the MSD ballast resistor. So again all running good until I get on the road and the motor spits and almost hesitates. So I go through countless threads and nothing is working! Did I do something wrong? Do I need to look more at the simple stuff? Where do I begin? Any help would be appreciated! Posted via Mobile Device |
03-19-2018, 11:33 AM | #2 |
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Re: 69 Chevy 250 motor
Make sure the accel. pump in the carb is working. With the engine off, look down the throat of the carb & work the throttle. A squirt of gas should squirt into the throat on each stroke. There is a little wire link that goes from the throttle shaft to the accel. pump lever. Often that link falls out of the hole. You might need to o-haul the carb & check the float level.
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03-19-2018, 11:36 AM | #3 | |
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03-19-2018, 11:40 AM | #4 |
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So I checked the carb last night it looked like there was PLENTY of fuel going in when I checked it with the truck off. Also checked to see if the fuel pump was still good I had a ohhhh fuel to fill a Gatorade bottle with in 30 seconds. Pulled the carb off and found a lot of junk in the float bowl so I cleaned it and reinstalled the carb. It seemed to run a lot better but still under load it would hesitate
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03-19-2018, 11:52 AM | #5 |
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Re: 69 Chevy 250 motor
melted wires, smoking wires and what the hell did a bush fix entail?
You didn't specify so I assume it still has a points ignition. it sounds like the wire you ripped out was the original ballast resistor wire, which would explain the need for the MSD ballast resistor. Running without the resistor would burn the points or at least cause severe pitting. Replace points and check dwell and timing. Looking at other areas (carb) and throwing parts at an unknown problem will send you in the wrong direction. Work one problem at a time.
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03-19-2018, 12:06 PM | #6 | |
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03-19-2018, 12:09 PM | #7 |
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So I was planning on replacing the coil plugs and wires reguardless
The old coil had its own ballast which was removed when I put the new one on. The melted wire happened prior to changing all that out. The wire was run to the ignition from the starter cilinoid which another wire was on the same pole one the cilinoid which went to the coil all running fine after the wire was replaced. Not my issue. Posted via Mobile Device |
03-19-2018, 12:11 PM | #8 | |
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03-19-2018, 01:16 PM | #9 |
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Re: 69 Chevy 250 motor
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03-19-2018, 04:06 PM | #10 |
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Re: 69 Chevy 250 motor
If your truck was sitting for a long time, you may need to clean the gas tank. I had that same issue. While the tank had been cleaned, it wasn’t clean enough. I kept having to remove the carb, take it apart, and clean it using carb cleaner and thin wires to run down the little ports. It would run fine for a while then start hesitating and running like crap after a while.
It finally started running really well after all the junk came out of the tank. Posted via Mobile Device |
03-19-2018, 05:59 PM | #11 | |
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Re: 69 Chevy 250 motor
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03-19-2018, 09:48 PM | #12 |
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Re: 69 Chevy 250 motor
https://www.youtube.com/watch?v=W94iksaQwUo
Stop working on the truck until you have educated yourself. on how it all works. Replace the points and condenser. Or repalce them with a magnetic pick up.(recommended) http://67-72chevytrucks.com/vboard/s...d.php?t=148346 Chinese HEI's are junk. Try removing the fuel filter before the pump. The pump is gravity fed. Last edited by phat69; 03-19-2018 at 10:18 PM. |
03-19-2018, 10:35 PM | #13 |
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Re: 69 Chevy 250 motor
Yup. Purple wire to "S" terminal, yellow wire to "R" terminal. They should never be on the same terminal.
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03-19-2018, 10:44 PM | #14 |
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Re: 69 Chevy 250 motor
To eliminate any fuel problems, get the number off of your carb and order a rebuild kit and rebuild the carb. I purchased mine from Quadrajet Parts for less than $50.00. I would also find a good clean replacement fuel tank if yours is rusted. I put a fuel filter before the fuel pump and after the fuel pump. Some say not to install a filter before the fuel pump but I haven’t had any problems. Check the filter sock on your sending unit as well. Good luck!
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