QJet Questions

• Oct 22, 2024

• #1

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Kilian

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I'm in the middle of a QJet rebuild and have a couple of questions.

The carb that I'm using does not have electric mixture control (blue connector on air horn) but it's missing the black plastic insert that is shown being used in place of the mixture adjusting solenoid. Is this insert needed or something that would have sometimes been left out at the factory? Not sure if the carb has been apart in the past to know if a PO just discarded it.

How do I check the electric choke for proper operation? Can I use a battery charger etc. to apply power and see what it does?

Thanks for the help.

 

• Oct 23, 2024

• #2

JoeR Jr

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From the sound of it, you have a carb that pre-dates the MC Solenoid. If so, there's no cutout for the solenoid. No insert is missing.

Unless the choke coil is physically damaged or corroded, it's unlikely that it's bad. But yes, you can put 12V to it and watch it move.

Joe

 

• Oct 23, 2024

• #3

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Kilian

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JoeR Jr said:

no cutout for the solenoid. No insert is missing.

Click to expand...

Thanks for the reply. My QJet has a hole that the solenoid would have fit into, right now it's just an empty space that is open to the float cavity. Some of the carbs I've seen online have a black plastic cup that fits down into the hole to fill the space.

 

• Oct 25, 2024

• #4

fast 99

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Does it have a TPS connector? Pictures are easy to post.

 

• Oct 25, 2024

• #5

Memaloose

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A battery is better to test with than a charger.

 

• Oct 28, 2024

• #6

75gmck25

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You need a battery or a 12 volt power supply for testing, not a battery charger. Even a bunch of D cell batteries taped together can give you the 12 volts. A battery charger may work, but the output can spike quite a bit when very lightly loaded.

 

• Oct 28, 2024

• #7

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Kilian

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75gmck25 said:

spike quite a bit when very lightly loaded.

Click to expand...

OK, thanks for the info.

 

• Oct 28, 2024

• #8

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Kilian

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fast 99 said:

Does it have a TPS connector? Pictures are easy to post.

Click to expand...

No electrical connectors for the carb. Thanks.

 

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• Oct 28, 2024

• #9

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racprops

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Those old carbs have two major problems, leaking caps/plugs between the throttle body and the bottom of the bowl body under the main jets. While you cleaning and rebuilding you need a sealing kit for those plugs,

Second is if it is still a steel shaft in aluminum body for the throttle plates and you do not see any bronze inserted tubes for the shaft you most likely to have a fair amount of ware which causes vacuum leaks.

If you not set up to rebuild the throttle body a good carb shop can do them.

A old timer car guy.

Rich

 

• Oct 28, 2024

• #10

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Jimmyperf400

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Just buy a new older style Q-jet and solve any problems you have the mid non and electric fuel control where nothing but junk. Thats where the name quadra junk came from. Otherwise the Q-jet is by far the best carburetor buelt if you understand how and what they can do.

 

• Oct 30, 2024

• #11

ButchM

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75gmck25 said:

You need a battery or a 12 volt power supply for testing, not a battery charger. Even a bunch of D cell batteries taped together can give you the 12 volts. A battery charger may work, but the output can spike quite a bit when very lightly loaded.

Click to expand...

Kilian
What he said.
Using a battery charger as a power supply is pretty much never a good idea, use jumpers from a battery. Battery chargers were not meant to be power supplies and can (have) give confusing/ambiguous results while troubleshooting.
As for the choke coil, I would first check with a VOM between the elect connector and the body looking for open or shorted (if either, trash and get another). If you have some resistance reading, while removed, hook it up and observe the coil unwind. If it does, you should be good. They are a fairly reliable piece in my experience, just need to get them adjusted correctly.