Fuel Line Replacement on the 2012 Polaris Sportsman Big Boss 800 6x6
Shop parts for a 2012 Polaris Sportsman Big Boss 800 6X6 ATV.
Six wheels, a dump box, and an 800 twin make the Big Boss a hauling machine first and a trail machine second, and its fuel plumbing reflects that. The 2012 Sportsman Big Boss 800 6x6 is electronically fuel injected, which means there is no petcock hiding under the tank to shut off flow and the hose you are about to replace is part of a pressurized circuit fed by a pump mounted inside the tank. On an older carbureted utility quad you would simply rotate a fuel valve to OFF and start pulling clamps. Here, pressure comes off the system first, and everything else follows from that.
Working Safely Around a Pressurized Fuel Circuit
Gasoline vapor is heavier than air, so it settles and lingers at floor level exactly where a work light or a battery charger tends to sit. Roll the Big Boss outside or open the shop up end to end before you loosen a single clamp, and keep every spark source, cigarette, and heater well away from the machine. Nitrile gloves are not vanity, either — gasoline pulls the oil straight out of your skin and carries whatever it dissolves through it.
To relieve pressure on this model, pull the fuel pump fuse or its relay, then crank the engine for a few seconds until it stumbles and dies. Switch the key off and disconnect the battery negative cable. That sequence bleeds the rail down to near zero and prevents the pump from priming while you have a fitting open. Carbureted machines skip this entirely; the fuel valve does the work for them.
Why Hose Goes Bad in the First Place
Rubber fuel line is a consumable, not a permanent part. Over the years the plasticizers that keep the hose supple migrate out, and a line that was once soft enough to bend by hand turns stiff and slightly glassy. Once the wall loses its flexibility, the constant heat cycling from the 800 twin plus the chassis flex of a long six-wheel frame drives hairline cracks into the surface.
Dry air speeds that up. Riders in arid country routinely find hose that has hardened years earlier than the same part in a humid climate. Ethanol-blended pump gas works the opposite direction, attacking the inner liner from inside and softening it while the outside continues to cure. A Big Boss that spends slow months parked with E10 sitting in the line can develop gumming and internal flaking that never shows on the outside at all.
Symptoms Worth Catching Early
A tired line rarely fails without warning. Look for:
- Fuel pooling on the skid plate or dripping onto the floor after the machine has been shut down and parked
- A gasoline smell that hangs around the tank area, strongest immediately after shutdown while residual pressure is still trapped
- Visible surface cracking, a chalky white cast, or a section that feels rigid when pinched
- Bogging under load, hesitation when you get into the throttle with a full box, or a general fuel-starved feel at higher rpm
- A dust-caked ring at a fitting, which is dried evidence of a slow weep
Because this is an injected machine, a leak on the pressure side may atomize and evaporate rather than drip. Your nose will often beat your eyes to the diagnosis.
Gathering Parts and Tools
Have it all within reach before anything comes apart:
- Replacement hose rated for injection pressure, matched to the factory inside diameter — low-pressure carburetor hose will not survive here
- New clamps in the correct style, plus a quick-disconnect release tool if your Big Boss uses a locking coupler at the pump flange
- Line-clamping pliers for pinching off any low-pressure or vent section, since no petcock exists to do it for you
- An approved fuel container and a shallow catch pan
- Rubber or nitrile gloves, plenty of shop rags, a flat-blade screwdriver, and a basic socket set for the seat, cargo box hardware, and side panels
Removing the Old Hose
Lift the seat and pull whatever plastics stand between you and the tank. Slide the catch pan under the fitting you intend to open and drape a rag over it, because even a depressurized line holds residual fuel that will run the moment the connection breaks. Back any worm-gear or spring clamp well down the hose before you disturb the joint.
Quick-connect couplers get squeezed squarely on their tabs and pulled straight off. Do not lever them sideways — the plastic collars grow brittle over a decade and split when pried. If the hose has varnished itself onto a barb, twist it gently to break the bond rather than hauling on it, or slit it lengthwise with a razor blade and peel it off the fitting.
Trace the routing as the old line comes free. The Big Boss carries a longer chassis than a standard four-wheel Sportsman, so the run passes more frame crossmembers and clips on its way aft, and the on-demand all-wheel-drive hardware up front adds clearance points a two-wheel-drive quad simply does not have. Note every retainer before the hose is fully out.
Installing the New Line and Confirming It Holds
Cut the replacement to the original length exactly. Extra hose chafes on the frame or drifts toward hot exhaust, and short hose puts tension on the fittings. Push each end fully onto its barb, dry — no grease, no oil, no silicone. Lubricant on a sealing surface gives pressurized fuel a path to creep out under the clamp. If the hose is stubborn, dip the end briefly in hot water to soften it.
Seat new clamps just behind the raised bead on each fitting and tighten them evenly rather than crushing the hose. Where a self-locking quick-connect is used, push until the collar clicks and tug firmly to verify it latched; that joint needs no clamp at all. Reseat the line in its original clips so it stays clear of the driveline and exhaust.
Reinstall the fuse, Reconnect the battery, and cycle the key on and off several times without cranking. Each cycle primes the pump and pressurizes the circuit, letting you inspect both joints while the surrounding area is still dry. Wipe everything clean, then idle the engine and check again. One last note on this platform: the fuel filter lives inside the tank as part of the pump module rather than inline where a carbureted machine would put a serviceable float bowl drain and filter. If delivery problems continue after a clean hose install, that in-tank assembly is where to look next.
Related Shopping Categories
Shop Fuel Lines for a 2012 Polaris Sportsman Big Boss 800 6X6 ATV.
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Shop Fuel Filters for a 2012 Polaris Sportsman Big Boss 800 6X6 ATV.
Shop Fuel Stabilizer for a 2012 Polaris Sportsman Big Boss 800 6X6 ATV.
Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your ATV's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.