QJet Questions

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

K

Kilian

Full Access Member
Joined
Mar 25, 2018
Posts
210
Reaction score
37
Location
Wisconsin
First Name
K
Truck Year
1983
Truck Model
C2500 on its way to a K2500
Engine Size
350
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.
 
JoeR Jr

JoeR Jr

Full Access Member
Joined
Jun 23, 2018
Posts
196
Reaction score
251
Location
Stokesdale, NC
First Name
Joe
Truck Year
1986
Truck Model
C10
Engine Size
6.0/4L80E
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
 
K

Kilian

Full Access Member
Joined
Mar 25, 2018
Posts
210
Reaction score
37
Location
Wisconsin
First Name
K
Truck Year
1983
Truck Model
C2500 on its way to a K2500
Engine Size
350
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.
 
Memaloose

Memaloose

Full Access Member
Joined
Dec 2, 2018
Posts
543
Reaction score
1,593
Location
Dolan Springs, AZ
First Name
Tony
Truck Year
1975
Truck Model
K20
Engine Size
350
A battery is better to test with than a charger.
 
75gmck25

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,254
Reaction score
2,194
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
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.
 
K

Kilian

Full Access Member
Joined
Mar 25, 2018
Posts
210
Reaction score
37
Location
Wisconsin
First Name
K
Truck Year
1983
Truck Model
C2500 on its way to a K2500
Engine Size
350

Attachments

  • 20241022_162520.jpg
    20241022_162520.jpg
    142 KB · Views: 26
R

racprops

Junior Member
Joined
Dec 22, 2023
Posts
14
Reaction score
17
Location
Phoenix AZ
First Name
Richard
Truck Year
1993
Truck Model
G20 Van
Engine Size
383
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
 
J

Jimmyperf400

Junior Member
Joined
Mar 29, 2022
Posts
15
Reaction score
13
Location
06606
First Name
Peter
Truck Year
1990
Truck Model
Full size gmc jimmy
Engine Size
Sbc 400
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.
 
ButchM

ButchM

Junior Member
Joined
Oct 19, 2023
Posts
22
Reaction score
30
Location
Idaho
First Name
Butch
Truck Year
1986
Truck Model
K30
Engine Size
454
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.
 
You must log in or register to reply here.

Similar threads

M
First qjet carb swap- sanity check
Replies
3
Views
345
Rusty Nail
Rusty Nail
T
Electric Choke Issues
Replies
6
Views
517
Matt69olds
Matt69olds
S
85 GMC Engine Wiring Questions
Replies
9
Views
1K
AuroraGirl
AuroraGirl
Kevin Foust
Rear axle seal questions.
Replies
8
Views
626
Juggernaut
Juggernaut
projectmidnight74
Finishing Electrical Remodel-Fuse Questions
Replies
3
Views
543
projectmidnight74
projectmidnight74

Latest posts

Forum statistics

Threads
44,116
Posts
949,576
Members
36,211
Latest member
112kee
Top