4K Carburetor - $140.00
NOTE: As of January 10, 2018 until further notice, we will not offer the 4K carburetor - the importer we have used cannot provide a worthy carburetor. We have tested a number of these and have found all suffer from internal defects, not yet identified (you can remove the fuel screw completely and carburetor still runs lean). When we find a solution or another source we will again provide this option.
Pictured is a Toyota 3K carburetor (21100-24045). Noted for its simplicity and ease of use. We buy chinese manufactured carburetors (there are no American Made carburetor replacements available for these older model Toyota Carburetors). The 4K is best used on the 1.6 Liter 8 Valve engines used in the Suzuki Samurai Liter. But this is not just another carburetor.
We buy carburetors from a single supplier whom we have built a relationship with. We take each carburetor and give it a thorough inspection for debris, float settings, leak points, wrinkled gaskets and poor linkage alignment. Since we have used this style carburetor for years, we know where the weak points are. Next we install the carburetor on our Shop Samurai (aka Fat Rat) and adjust cold idle, hot idle and fuel settings. We idle the engine down low to make sure the idle circuit is the only circuit keeping the engine running. We set the fuel screw for highest vacuum and make final tiny adjustments with an Innovative Air/Fuel Wide Band O2 Sensor. Now we adjust the idle for 800 rpm and go for a test 4 mile drive (yes we drive them in a car - not a flow bench). When completed, our carburetors start immediately, idle correctly and will take throttle blips without stumbling.
Not all carburetors can pass our process. These are stacked on a shelve for later examination. When we collect a few, we sit down and overhaul these top to bottom, often finding the errors from manufacturing, misdrilled holes or missing components. Over the past 5 years, we have found 25% that fail our process. Buying from us assures you have a carburetor that will fire up and run - right out of the box (or plastic bag, in this case).
WHAT'S THE DIFFERENCE?
3K VS. 4K CARBURETOR
There are a few differences between the Toyota 3K and Toyota 4K carburetors.
Idle Air Compensator (IAC):
The 3K has internal IAC :
On the “head side” of the carb is a small metal cover - this is the IAC. As the carburetor gets hot from the heat around it, a bi-metallic spring expands and allows additional air into the carb throat through internal passageways. The 4K has these features in the carburetor casting, but are not machined to accept the IAC.
The 4K has external IAC:
This is the rectangular metal box on the “fender side” of the carb. This has an inlet rubber hose (from the top of the carburetor horn) going to the IAC box and an outlet rubber hose (to the base of the carburetor).
Fuel Cut-Off Solenoid
The 4K carb has an additional, 12 volt, Fuel Cut-off Solenoid to prevent “dieseling” when the engine is shut off.
The 3K carburetor has internal machining completed to accept this Fuel Cut-Off Solenoid. A hex plug is screwed into the 3K carb housing blocking the ports off when not used.
All other features of both carbs have been identical:
Jets sizes: 100 primary/ 150 secondary
Air bleeds: 0.021 diameter
Bore sizes: primary and secondary
Needle and Seat Sizes
Fuel tube size
(Note: We know of no source for “hard parts” to fit these carbs, but there are a number of American Made rebuild kits on the market. We hope to have these listed in the future for your reference.)