I Need Systematic Help

[LaryHill]

This is perhaps making too many changes at once. About a month ago, I decided that I would change my '71 1.9 GT over to a Pertronix electronic ignition. I also thought it would be a good time to fine tune my 32/36 with a new arangement of jets. While waiting for my jet pack to come, I installed the ignition conversion. Near the end of the conversion, I discovered that I was sent the 1.5 ohm coil in error. Wanting to hear the engine pur, I kept the clear risistor wire in place and and used the 1.5 ohm coil.
Everything appeared to be fine, but I thought it would be better to go to the recommended configuration. I used my Diamond 3.0 ohm coil and took the resistor wire out of play and go with the 14 guage modification. I just started it and did not perform any tests. I did think that it did not have the vigor as the 1.5 coil configuration, but by then my jets had arrived. Here is the sequence of what happened next.
1) I took the carb off and rebuilt it. It was the standard $30 rebuild
kit, and this was about my 6th rebuild in my lifetime. I did not make
any jet changes and I felt comfortable with my work.
2) I set the screws for adjusting, and everything appeared to go well.
Three out on the a/m and 1.5 in on the i/s. All the time I was feeling
good, the idle was responding as the book said.
3) Now it was time to go through all the tests. I tried to race the
engine and found that it died out at about 2000 rpm. My first thought
was that I left something out of the carb, or did a sloppy job of
cleaning it.
4) It appears as though the carb in not making the transition from primary
to secondary. Just like the fuel or air cut off.
I need help in eliminating either the carb or coil. The bleeding is the money and time being spent going back and forth. I need someone to point me in the right direction.

Larry

[nobody]

If it were me I would back track a bit. to be specific I would put the points back in and do the carb. That way at least you aren't fighting and wondering. JM2CW

[madhatterpdc]

You might want to check the ignition timing and check the carb base for vacuum leaks. The little magnetic collar that goes around the distributor shaft can sometimes be forced on misaligned.

It might be helpful to know more about what happens when it dies, does it cut out clean, does it bog or stumble, stall?

[tekenaar]

Originally Posted by LaryHill This is perhaps making too many changes at once. About a month ago, I decided that I would change my '71 1.9 GT over to a Pertronix electronic ignition. I also thought it would be a good time to fine tune my 32/36 with a new arangement of jets. While waiting for my jet pack to come, I installed the ignition conversion. Near the end of the conversion, I discovered that I was sent the 1.5 ohm coil in error. Wanting to hear the engine pur, I kept the clear risistor wire in place and and used the 1.5 ohm coil. Everything appeared to be fine, but I thought it would be better to go to the recommended configuration. I used my Diamond 3.0 ohm coil and took the resistor wire out of play and go with the 14 guage modification. I just started it and did not perform any tests. I did think that it did not have the vigor as the 1.5 coil configuration, but by then my jets had arrived. Here is the sequence of what happened next. 1) I took the carb off and rebuilt it. It was the standard $30 rebuild kit, and this was about my 6th rebuild in my lifetime. I did not make any jet changes and I felt comfortable with my work. 2) I set the screws for adjusting, and everything appeared to go well. Three out on the a/m and 1.5 in on the i/s. All the time I was feeling good, the idle was responding as the book said. 3) Now it was time to go through all the tests. I tried to race the engine and found that it died out at about 2000 rpm. My first thought was that I left something out of the carb, or did a sloppy job of cleaning it. 4) It appears as though the carb in not making the transition from primary to secondary. Just like the fuel or air cut off. I need help in eliminating either the carb or coil. The bleeding is the money and time being spent going back and forth. I need someone to point me in the right direction. Larry

Matter of semantics here, 1.5 ohm coil is "non-resistance" type while 3 ohm coil is "resistance" type. Personally, I'd rather use the "non-resistance" type coil with the Pertronix and leave the stock 12V coil wiring intact (two wires to the + side of the coil) for that extra ignition kick during starting. You would have to connect the Pertronix with a separate wire to a switched ("on" with key) 12V source in this scenario, which, in effect, is what you're doing with the 3 ohm coil also.

When you "cleaned/rebuilt" the carb, did you remove jets and holders while cleaning and clean them in separate solution? If you didn't remove them, very likely some scale in the passages got dislodged and is blocking a jet, but not in the "transition" passage as you think. Since it idles fine, you're problem is NOT in idle/transition phase. The "idle jet" actually meters fuel to a common "idle/transition" passage in the carb. "Idle jet" is and always has been somewhat of a misnomer and I SURE wish they wouldn't have called them that . . . very, VERY misleading!

At 2000 RPM, you're just starting to use the main jet of the primary and if it dies here more than just a bog, like you said, it's most likely a restricted/plugged main jet and/or passage problem.

[LaryHill]

Thanks to all who sent me in the correct direction. I found the problem. When I was handling my carb after cleaning, the auxiliary venturi on the primary side fell out. I quickly put it back in place. I did not check it again until the third time I back tracked my steps. You guessed it! I reinstalled it incorrectly. Your feedback kept me on the trail. Everything is fine now! Many thanks,
Larry