Air Intake & Fuel Systems
About Air Intake & Fuel Systems
A sled that sits all summer often comes out with stale fuel in the carburetor, a cracked flange or a hard diaphragm, and rides badly until the fuel system is put right. This category holds carburetor repair kits and rebuild kits, metering diaphragms, mounting flanges, jets, and fuel pump repair kits, mostly for Yamaha, Ski-Doo and Polaris machines.
Carburetor kits are listed by make, model and often the carburetor type, such as a TM40, so match yours. Check what a kit includes. Mounting flanges join the carburetor to the engine, and a cracked one lets air in and leans out the mixture. Jets are sold by number in packs, such as #45 and #90, and a higher number generally means a larger opening. Jetting changes with altitude and temperature, and a lean setting can damage an engine, so follow the manual or a jetting chart for your machine. For storage, the snowmobile winterizing checklist covers the fuel system.
Brands here include Vertex, Quantum, EPI, Mikuni and Parts Unlimited. Fuel work often goes with Exhaust and Engines & Components, part of Snowmobile. Pick your sled in the Ride Finder at the top of the page.
FAQs on snowmobile carburetors and fuel systems
How do I know if my snowmobile carburetor needs a rebuild?
Common signs are hard starting, a rough idle, bogging when you open the throttle, fuel smell or leaks, and gummy residue after storage. Try fresh fuel and a cleaning first, then rebuild with a kit made for your model.
Do I need to change jets when I ride at higher altitude?
On carbureted sleds, thinner air at altitude leaves the mixture richer, so smaller jets are often used. The right change depends on the model, so follow your manual or a jetting chart for your sled.
What does the diaphragm inside a snowmobile carburetor do?
The metering diaphragm moves with pressure changes and controls how much fuel passes to the engine. With age it stiffens or cracks, which causes poor running, so it is replaced when a carburetor is rebuilt.
Can a cracked carburetor flange cause running problems?
Yes. A cracked or loose flange lets air into the intake, which leans out the mixture and can cause a rough idle and hard starting. Inspect it whenever you work on the carburetor, and replace it with the one listed for your model.
