Snowblower Buying & CareThe common pitch says a rubber impeller kit fixes clogging and restores throwing distance, full stop. That pitch skips the first question the kit maker itself asks: how big is the gap between your impeller blades and the housing they spin inside? The instructions for the Snow Blower Impeller Kit state the window plainly. If the gap is less than 1/4 inch, you probably do not need the fix. If it is greater than 5/8 inch, you probably cannot use it. A kit fitted outside that window is not an upgrade. It is a modification in search of a problem.
The symptom: wet snow that dribbles instead of throwing
On a two stage machine, the front auger gathers snow and the impeller, the second set of vertical blades behind the auger, throws it up the chute. The kit instructions describe the failure exactly: a large space between the impeller blades and the cylindrical chamber lets snow and slush slip past the blades instead of being thrown. The slipped material builds up around the impeller and in the discharge chute, the chute clogs, and the snow that does exit leaves with less force behind it. Dry powder hides the problem for a while. Wet snow and slush expose it in one pass.
That description matters because it separates a gap problem from a weak machine. A gap problem shows up as slush packing around the impeller, repeated chute clogs in heavy snow, and a discharge stream that falls short even at full throttle. If the chute stays clear and the stream is simply shorter than it used to be in all snow types, the cause may sit elsewhere, and the next section comes before any drilling.
Rule out the free causes first
Friction. Paint on the auger, impeller, housing and chute is functional, not cosmetic: it protects the metal and lowers the friction snow travels over. As paint wears and rust forms, the rough surface slows travelling snow and costs distance. The documented repair is unglamorous and cheap. Clean the surfaces, remove rust, touch up the paint, and coat the chute and housing with a silicone polymer spray, which is water phobic, so snow does not stick to it.
Housing and impeller wear. Rocks and ice chunks passing through the machine can bend impeller wings and push the housing outward. That damage also enlarges the gap, but rubber paddles are not the correct first answer to bent metal. The documented repair is to re-form and weld cracked or bent wings, and to heat and hammer a distorted housing back, welding any tears closed, so the gap closes by restoring the parts. A housing torn or worn badly enough belongs in a shop, not under a drill in a driveway.
Travel speed. A snowblower throws farthest with a full housing. Moving too slowly underfills the housing and weakens the throw. Moving too fast overloads the engine, and wet or deep snow needs a slower pace than light snow. Before blaming hardware, run one pass at a steady speed that keeps the housing working full without bogging the engine down.
Planned step images for this guide: the gap being measured between an impeller blade tip and the housing; a rusted chute surface before cleaning and coating; a trimmed rubber paddle held against its impeller blade before drilling; the strap and bolts fitted on one blade; and the finished clearance being checked by hand turning the impeller with the engine off. Each image belongs at its step, showing the exact part or action the step names.
Measure the gap: the eligibility window
With the engine off and the machine made safe per your operator manual, the measurement is a simple one: the distance from the tip of an impeller blade to the housing wall it passes. Check more than one blade and more than one position, because a housing worn or distorted in one spot can read differently around the circle. Then apply the kit maker's own specification check:
| Measured gap | Kit verdict from the instructions |
|---|---|
| Under 1/4 in | Probably do not need the fix; look at friction and travel speed instead |
| 1/4 in to 5/8 in | The working window the kit is built for, on a two stage machine |
| Over 5/8 in | Probably cannot use the fix; suspect housing or impeller damage and price a repair |
| Single stage machine, any gap | Not eligible; the kit modifies two stage impellers only |
Inside the window, the kit specification is consistent across sellers. Each blade gets one rubber paddle, 1/4 inch or 3/8 inch thick and 2 inches by 5 inches, made from styrene butadiene rubber (SBR) with a minimum tensile strength of 725 PSI (5 MPa) and a durometer of 65 to 75. A punched metal strap, 1 3/8 inches by 3 3/4 inches and 1/16 inch thick, clamps the paddle with bolts and lock nuts. The kit models for three blade machines are sold as 1/4 inch (SBIK143) and 3/8 inch (SBIK383) versions, and four blade versions carry the same paddle specification.
The warranty and balance costs nobody lists
Two costs never appear on a kit listing. The first is warranty. Drilling an impeller is an alteration, and the warranty text in MTD and Troy-Bilt manuals is specific: damage resulting from the installation or use of any accessory or attachment not approved by the manufacturer will void the warranty as to that resulting damage, and coverage applies only where the product has not been subject to alteration. That does not mean the whole warranty vanishes the moment a drill comes out. It means a failure the manufacturer ties to the modification is yours to pay for. On a machine still under warranty, that risk is part of the price of the kit.
The second cost is balance. The instructions carry a warning in capital letters for a mechanical reason: fit a kit to every blade, because modifying only some blades causes harmonic imbalance in the spinning impeller, which can cause excessive wear on the impeller shaft bearing and a costly repair. Owner forums raise the same worry from the other side, with prospective installers asking about drilling holes through the impeller and about balance or rotation problems. The documented answer is not to skip blades. It is to fit every blade identically, trimmed to the tightest spot in the housing, so the rubber barely touches, if at all, rather than dragging.
Procedure: fitting rubber paddles the documented way
The kit instructions put installation at 1 to 2 hours depending on how handy you are, using a drill with a 3/8 inch bit, a bit extension, a ratchet set, and a utility knife. Work only with the engine off and the machine secured per your manual.
- Confirm eligibility first: two stage machine, gap measured between 1/4 inch and 5/8 inch, and no bent wings or torn housing that need repair instead.
- Count the impeller blades and buy or cut one paddle set per blade. Three blade and four blade machines take different kit counts, and a partial set is not a saving, it is the imbalance the instructions warn against.
- Trim each paddle to fit the spot where the gap is smallest. The instructions are explicit that the rubber must be fitted to the tightest point, otherwise the rubber will fail.
- Position the paddle and strap on the blade face, drill the blade, and bolt the strap down with the supplied bolts and lock nuts. Repeat identically on every blade: same position, same trim logic, same hardware.
- Turn the impeller slowly by hand and watch each paddle pass the housing. The target fit from owner practice and the kit guidance is rubber barely touching, if at all, with no catching on ridges or seams.
- Run the machine briefly with no snow, stop, and recheck that every strap is still tight and every paddle is intact before the first real pass.
What success looks like: hand turned, every paddle clears the housing evenly with no hard drag and no loose hardware. Under load in wet snow, the chute stays clear through a full pass, the discharge leaves as a stream rather than dribbling blocks, and no new vibration appears at full throttle. New vibration is a stop signal, not a break in period: it points back to an uneven fit or a loose strap.
Decision: kit, repair, or leave it alone
The decision framework is short because the measurements do the work. Gap inside the window, housing sound, machine out of warranty or the warranty risk accepted, and the free causes already checked: the kit is a reasonable, reversible enough job at the cost of drilled blades. Gap outside the window, or damage found during measuring: the honest fix is housing or impeller repair, which is a shop job when welding is involved. Gap small and throw still short: spend nothing, clean and coat the snow path, and work on travel speed. A kit was never the answer to a friction problem.
, Owen Park, Automotive Writer