How often should the carb be rebuilt?
Issue:
84' GSL
Strarts, accelerates OK, but when holding at 3500rpm it has a slight stutter. Stutters at other rpm's if held.
The last rebuild was in 1997 at 120k miles when my father had an Atkins rebuild installed. It now has 175k miles.
The roads have been salted so the car is hibernating in the garage.
A carb rebuild would be this winter or early spring.

What I did earlier this year (2024):
Ignition:
Replaced Spark Plugs, Distributor Cap & Rotor
Replaced Spark Plug Wires and Coil to Distributor Wires
Replaced Coils
Tested Ignitors – both good
Set Timing Leading and Trailing
Timing Light tested all Ignition Wires

Vacuum leak found and fixed:
Verified all Rats-Nest Solenoids working properly
Replaced larger hose from Carb to Purge Valve intake
Replaced return hose from Purge Valve to Carb – startup puff
Replaced Vacuum Hose to Purge Valve
Replaced hose from #1 Anti-Afterburn to Intake Manifold
Replaced #2 Vacuum Diaphragm (choke) – vacuum leak
Replaced Trailing Vacuum Advance – vacuum leak

Flue/intake
Replaced Air Filter
Replaced Fuel Filter
Tested Flue Pump: 3.0 psi, 1400cc output in one minute
Checked Carb Float Levels – both good
Clean Carb In and Out – Double dose Seafoam
Set Idle Mixture and Idle Speed
Drain Gas Tank – some initial black liquid, some small flakes
Heet added to full tank of gas

Other:
Removed Hot Start Assist
Removed Sub-Zero Start Assist – capped off fluid feed to carb
Change Transmission & Differential Gear Oil
Replace Pre-Heater Hose & Hose Clamps

Any any all suggestions will be greatly appreciated.

 

Sounds like you have done almost everything short of a carb rebuild. Is it still the original Nikki? Atkins has the rebuild kits ($105).

Mine flutters at around 3100 rpm but it's just the secondary's kicking in, love that little boost it gets.

 

If you do decide to rebuild it, do not use the needle valve and seats in the rebuild kits. You should re-use your existing needle valve and seats (new ones are not machined properly and you will have inconsistent flooding and or no fuel flow).

 

Yes it is the orginal Niki.
I bought a rebuild kit mayb3e 15 years ago when the acelerator pump started leaking gas.
Earlier this year I did get the one from Atkins.
I do have a tendency to buy parts I think I might need in the future, so I also have the Mazda spacer that goes under the carb.

 

Thanks.
Good to know.

 

I have no prior experience with rebuilding a carb. I previously downloaded the Mazda Carburetor Manual, and I'm working through the theory and operation section.
Lots of parts and steps. I am familiar with the on vehicle adjustments.
I will follow the same methodology I used for rebuilding the 12a, lots of zip lock baggies labled for parts and lots of photos to record the disassembly.