Slide Carburetor

JW Slide
Carb

Traxxas Size

Change the carburetor and a Traxxas 3.3 becomes much easier and more consistent to tune. It also picks up a bunch of power. This is the same legendary carburetor that ships on our JW12 Gas Truck engines, machined to fit the Traxxas 2.5 and 3.3.

$69.99
In stock, ready to ship
Will it fit my truck?
Classic RC JW slide carburetor fitted to a Traxxas 3.3 nitro engine
Fig. A · Part 3120039 · shown fitted to a Traxxas 3.3, engine not included
Made in Italy
Manufactured by Nova Engines, exclusively for Classic RC Company.
Machined to fit
The JW12 race carburetor, machined for the Traxxas 2.5 and 3.3.
Sold by people who run it
Call us and you talk to someone who has had one apart.
Classic RC JW slide carburetor, Traxxas size, for nitro RC truck engines
$10.00 off
In stock

Pickup available at 585 S Ferdon Blvd

Usually ready in 1 hour
Vehicle Compatibility
  • Traxxas Jato 3.3
  • Traxxas Slayer 3.3
  • Traxxas Revo 3.3
  • Traxxas Nitro Rustler
  • Traxxas Nitro Slash
  • Traxxas 2.5 Engine
  • Traxxas 3.3 Engine
View details

Change the carburetor and a Traxxas 3.3 becomes much easier and more consistent to tune. It also picks up a bunch of power. This is the same legendary carburetor that ships on our JW12 Gas Truck engines, machined to fit the Traxxas 2.5 and 3.3.

Why we made one

It is well known that simply changing the carburetor makes a Traxxas 3.3 much easier and more consistent to tune, and that it picks up a bunch of power on the way.

For years the answer was that the good ones were hard to find, and cost almost as much as the engine. That is no longer true. Prices came down and availability came back. The OS 11K is a good carburetor and we are not going to tell you otherwise.

What changed is what else showed up. Cheap copies of the 11K are on the market now, and they are worse than the stock carb you are trying to replace. From a listing photo you cannot tell which one you are getting.

So we had ours made, in Italy, by Nova. It is legendary for its supremely stable idle quality and easy tuning. A removable venturi lets you fine tune the power delivery.

You know who made it. You know who to call.

Why we made one

You already
know the fix.
Telling them apart
is the problem.

It is well known that simply changing the carburetor makes a Traxxas 3.3 much easier and more consistent to tune, and that it picks up a bunch of power on the way.

For years the answer was that the good ones were hard to find, and cost almost as much as the engine. That is no longer true. Prices came down and availability came back. The OS 11K is a good carburetor and we are not going to tell you otherwise.

What changed is what else showed up. Cheap copies of the 11K are on the market now, and they are worse than the stock carb you are trying to replace. From a listing photo you cannot tell which one you are getting.

So we had ours made, in Italy, by Nova. It is legendary for its supremely stable idle quality and easy tuning. A removable venturi lets you fine tune the power delivery.

You know who made it. You know who to call.
Anatomy
Fig. 1 · Part 3120039

What you are actually buying

Side view of the JW slide carburetor mounted on a Traxxas engine, with numbered callouts
1
2
3
4
1
Removable venturi · 7.5mm included
A fine tuning lever, and the next section is about nothing else.
2
Fits your Traxxas air filter boot
Your original Traxxas air filter boot goes straight back on.
3
Cast and machined in-house at Nova
Body and spigot are full aluminium, cast and machined in the same shop in Italy. The 11K uses a spigot insulator and those are known to crack. There is nothing there to crack on this one, and the thermal transfer worry you sometimes hear about is unfounded.
4
Throttle linkage
Ships with a Nova throttle arm, and it also takes your original Traxxas arm. The OS 11K does not. The Traxxas arm is sold separately if you need one.
A fine tuning lever

The venturi comes out

Pulling the venturi lets you shift where the power lands. Yours arrives with the 7.5mm already fitted, and for most people that is where it stays.

Smaller favours low rpm torque. Larger favours mid range and a higher max rpm. It is a fine adjustment, not a transformation.

If you are running a Revo 3.3, the low profile one is not optional.

Close-up to come
7.5mm
Supplied, fitted
What ships on the carb. Leave it alone and it works.
Close-up to come
Gold aluminium
Classic RC · 6.0, 6.5, 7.0mm
Easier to fit and to get back out again. It also looks good, which is not nothing.
Close-up to come
Low profile
Aluminium · 6.0, 6.5, 7.0, 7.5, 8.0mm
Improves torque across the full rpm range, and it is what clears a Revo 3.3.
We do not stock the plastic venturis. Aluminium only, in the sizes above.
Fitment Seven trucks, seven honest answers

Will it fit
my truck?

Pick what you are running. You get the real answer, including the two trucks that need a second part or a modification before they will go together.

Traxxas Jato 3.3
Fits. Nothing to modify.
Before you order
The engine is not included. This is the carburetor only.
What you get
The carb, with the 7.5mm venturi already fitted. Bolt it on, set the needles, go run it.
Running something not on this list? Call the shop. We would rather talk you out of the wrong part than sell you one.
Whichever one you are running, I set the needles by hand on every carburetor before it ships.
Before you buy

The fine print, up front

Three things that catch people out. We would rather you read them here than find out on the workbench.

01
Revo and Slayer need a change
Both need the venturi trimmed, or a low profile venturi in place of the one supplied. Every other truck on the list bolts straight on.
02
Stock flywheels are fine
Stock Traxxas flywheels clear without trouble. The one to watch is the optional 40mm Revo wheel, which does not fit.
03
The engine is not included
You are buying the carburetor. The engine in these photos is ours, and it stays here.
Technical Resources

Manuals, exploded views, tuning notes

Everything we have on this carburetor, in one place, free, no email required.

Factory settings and break in
Where every needle leaves our bench, what the idle gap is set to, and how to take it from there.
Exploded view
Not published
Venturi chart
Every size we stock, gold and low profile, and what each one does to the power delivery.
Technical Schematics
Download Manual
Read →
On the bench
Four views · our own photographs, not the supplier catalogue
Front view of the JW slide carburetor showing the bore
Front, looking into the bore
Three quarter view of the carburetor fitted to the engine
Three quarter, from the crank
Rear view of the engine with the carburetor fitted
Rear, showing the mount
Angled view of the carburetor sitting low on the engine case
How low it sits on the case
Specification

Everything we know about it

Part number
3120039
Type
Slide carburetor
Fits
Traxxas 2.5 and 3.3 engines
Venturi included
7.5mm, removable
Other venturis that fit
Classic RC Gold Venturis and Nova Engines Low-Profile Venturis
Maximum flywheel diameter
36mm
Manufacture
Made in Italy by Nova Engines, exclusively for Classic RC Company
Still not sure it is right for your truck?
Call the shop. We would rather talk you out of the wrong part than sell you one.
Ask us about fitment