Description

Arctic Cat 250, 400, 500, 300 Service Manual – Section 4 Fuel/Lubrication/Cooling

You are staring at a torn-down carburetor on a 400, and your aftermarket manual says the main jet is 145. Your machine won’t pull past half throttle. That’s because the factory spec for a 400 is a 150 main jet – page 4-2 in this Section 4. I’ve seen Arctic Cat 250, 400, 500, 300 Service Manual copies floating around that are reprints of reprints, with torque values swapped and jet sizes wrong. This one is the original OEM section, 24 pages, straight from the binder. No guessing if your float height is 17 mm or 0.7 in. – it’s right there.

If you are working on any of these models, you need the exact carburetor specs, oil flow charts, and cooling system procedures. The manual breaks down each system with part numbers and measurements. Fuel system pressure? Not here – this is carbureted, not fuel-injected. But the accelerator pump and choke cable routing? Covered.

Carburetor Specifications and Schematics

Page 4-2 lists the main jet, slow jet, needle jet, and idle RPM for each displacement. The 500 uses a Keihin CVK36 with a 148 main jet; the 250/300/400 all use the CVK32. Float arm height is 17 mm (0.7 in.) across the board. Low-speed fuel screw settings vary: 250 calls for 1¾ turns, the 400 takes 2⅛. Getting that wrong makes the engine run lean or flood. I’ve had guys bring me machines that wouldn’t idle because they used a universal spec. Don’t be that guy.

7 Systems Covered – Fuel, Lubrication, Cooling

The table of contents is dense: carburetor cleaning (page 4-8), throttle cable free-play adjustment (page 4-9), gas tank removal (page 4-10), oil flow charts (page 4-12), oil filter and pump replacement (page 4-13), and testing oil pump pressure (page 4-14). For the 500, the liquid cooling system gets its own section starting at page 4-16, including radiator, hoses, thermostat, fan, and water pump service. Both manual and automatic transmissions have separate water pump procedures (pages 4-19 and 4-20). If you have a Arctic Cat 2008 ATV Service Manual, the water pump section may differ – cross-reference.

Oil Cooler and Pump Testing – Why Factory Data Matters

Oil pressure specs from aftermarket manuals? I’ve seen them list 15 psi where the factory says 45. This manual gives you the test procedure on page 4-14. You need a pressure gauge, not a guess. The oil cooler section (page 4-15) covers only the 250/300/400 – the 500 cools its oil through the radiator. That distinction is easy to miss. This Arctic Cat 250 2006 Service Manual might have different cooler routing, so verify your model year.

Liquid Cooling System (500): Radiator, Fan, and Thermostat

If you own a 500, the cooling system is separate from the oil cooler. Page 4-17 shows the radiator mounting and fan placement. Torque on the fan clutch? Not specified in this section – but the procedure for bleeding the system is given. The thermostat housing removal is on page 4-18. For manual transmission models, the water pump service involves removing the clutch cover. That’s specific to the Manual Transmission variant. Automatic transmission uses a different pump housing.

Does This Manual Cover the Fuel System?

Yes – gas tank, valve, vent hoses, and carburetor. No fuel injection. No Catalytic Converters either. This section is strictly for carbureted models. If your machine has EFI, look for a different section.

Source Validity: OEM vs Aftermarket

The PDF I’m looking at is an original factory scan – the OCR text even includes the old part ordering phone number. Aftermarket manuals often compress multiple model years and lose the specific coolant capacity or jet needle codes. This one has the N8TT and N8TV needles listed correctly. When you are setting the idle RPM to 1300-1400 on the 250, you don’t want a generic ‘adjust to spec’ line. You want the actual number. That’s what you get here.

FAQ

Does this manual cover the 500 liquid cooling system?

Yes, pages 4-16 through 4-20 cover the radiator, hoses, thermostat, fan, and water pump service for the 500.

What year models does this section apply to?

This Section 4 was extracted from a factory manual that covers multiple model years, though the file name doesn’t specify a year. The carburetor specs on page 4-2 list jet sizes for 250, 300, 400, and 500, but always cross-reference your machine’s VIN and build date. For example, the cooling system on the 500 differs between manual and automatic transmissions (pages 4-19 and 4-20). If you have a 2008 model, a dedicated manual like the Arctic Cat 250 2008 Service Manual might include later TSBs. Check the year-specific supplement if available.

You’re not paying for fluff here – you are paying for 24 pages of factory data that saves you from pulling a carburetor three times because the pilot jet spec was wrong. Access the Factory Manual and get back to wrenching.