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What the HIPA C1T-W33 tune-up kit covers

The HIPA Carburetor for Zama C1T-W33 (P/N 586936202) is a factory pre-tuned replacement diaphragm carburetor built for the Husqvarna 240, 240E, 235, 235E, 236, and 236E chainsaws, plus the Jonsered CS2234 and CS2238 cross-compatible saws.

It ships as a complete 7-piece bundle: carburetor body, RB-149-spec gasket and diaphragm set (Zama GND-83 equivalent), primer bulb, fuel line, fuel filter, air filter, and spark plug. One purchase refreshes the full fuel delivery and ignition chain, which cuts down on repeat repairs caused by leaving worn lines or filters in the system.

For the 2026 service cycle, the unit is built to meet or exceed EPA Phase 3 evaporative emission thresholds for nonroad spark-ignition engines of 25 hp or less, and it aligns with CARB SORE maintenance-grade compliance for legacy equipment.

Genuine Zama or aftermarket?

It's a high-specification aftermarket unit, manufactured to Zama C1T-W33 and C1T-W33C dimensional and flow-bench tolerances. It directly replaces OEM numbers 586936202, 545072601, and 574719402 on a straight 1:1 interchange, and it stays serviceable with Zama RB-149 / GND-83 rebuild kits later in its life.

Fitment check before you order

Direct bolt-on fitment covers the Husqvarna 235 (2010-2020), 235E, 236, 236E, 240 (2010-2020), and 240E, all on the 38.2cc X-Torq 2-stroke platform. Jonsered CS2234 and CS2238 share the same Zama C1T-W33 carburetor architecture.

The mounting bolt pattern, throttle linkage geometry, and impulse port alignment match the OEM casting. You don't touch the intake manifold, air filter housing, or throttle cable. Check your saw's model badge against that list, then order.

Want a second bundle to compare? Koeep carries two companion listings for the same 586936202 cross-reference: the C1T-W33 carburetor tune-up kit for the Husqvarna 240/240E/235/235E and the Zama 586936202 replacement carburetor kit.

Full specification table

Every published number for this kit in one place:

Materials and metering, in plain terms

The diaphragm problem with ethanol fuel

Nitrile-rubber diaphragms, common in pre-2020 aftermarket carburetors, swell and harden after as few as 50 hours of E10 exposure. The result is metering lever drift and lean-running.

The HIPA diaphragm is a fluoroelastomer-enhanced multi-layer composite, cross-referenced to the Zama GND-83 and RB-149 specifications. It holds Shore A durometer within ±3 points after 200+ hours of E15 immersion. Soak tests show less than 5% volumetric swell after 500 hours submerged in E15 at 50°C, well inside the 15% acceptance threshold in SAE J1681.

Every fuel-wetted part uses ethanol-tolerant material: pump diaphragm, metering diaphragm, inlet needle tip, and primer bulb. The stated operating range is -20°C to +60°C, which covers winter storage through summer cutting.

Flow-bench calibration

Each unit is wet-flow tested on a calibrated bench that simulates the 38.2cc X-Torq engine's actual vacuum signal at idle (about 1,800 to 2,200 RPM), through part-throttle transition, and at wide-open throttle up to the 9,000 RPM governor limit.

The high-speed nozzle targets a stoichiometric-adjacent ratio of roughly 13.5:1 to 14.0:1 at WOT under ISO 1585 reference conditions. The idle circuit aims at 12.5:1, which keeps the off-idle transition stable on the X-Torq stratified scavenging design. Pop-off pressure comes factory pre-set at a nominal 10-12 psi.

Symptom mapping with DTC equivalents

A chainsaw has no OBD-II port and no CAN-bus, so there are no codes to pull. The workable method is symptom mapping: match what the saw is doing to a conceptual DTC range, then inspect the parts that range points to.

• P0171-equivalent (lean): surging at WOT, hesitation on a throttle blip, racing idle. Usually a stiff or leaking pump diaphragm, or a clogged inlet screen.
• P0172-equivalent (rich): four-stroking at WOT, wet-fouled plug, heavy exhaust smoke. Often a hardened metering diaphragm or an inlet needle that isn't seating.
• P0300-equivalent (random misfire): intermittent idle stall, erratic chain speed. Check for debris in the metering chamber or a perforated pump diaphragm upsetting fuel pulse delivery.
• P0505-equivalent (idle control): no idle without throttle input. Inspect the idle mixture circuit and the throttle plate seating in the C1T-W33 venturi bore.

The HIPA C1T-W33 tune-up kit resolves all four symptom clusters by restoring the carburetor's full metering integrity.

If you also service ride-on mowers, our Briggs & Stratton 14.50 305cc carburetor guide applies the same DTC mapping method to OEM cross-references on a larger engine.

Service life and 2026 compliance

Under normal consumer cutting, roughly 20 to 30 hours a year, the projected service life is 5+ years or 150+ operating hours on ethanol-free alkylate fuel. On E10 pump gas with seasonal stabilizer treatment, plan on 3 to 4 years or 100+ hours.

For maximum life, run alkylate fuel when you can get it, and treat any E10 or E15 with stabilizer before seasonal storage.

The compliance picture for 2026

Frequently asked questions