My Cub Cadet LT1045\’s Blades Will Not Engage

Boy on tractor mower A safety interlock system prevents LT1045 "power takeoff" engagement. Image Credit: Comstock/Comstock/Getty Images

Whenever you start a gas-powered push lawnmower, the blade engages automatically. The Cub Cadet LT1045 lawn tractor uses a "power takeoff," or PTO, system to operate the blade. This enables you to keep the blade from spinning when you drive the mower over concrete or other hard surfaces. Certain operational settings or engine conditions keep your blade from engaging.

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Safety Switch

A safety interlock system on the Cub Cadet LT1045 is designed to prevent damage to the mower, the operator or anyone nearby. This includes blade engagement: if the driver leaves the seat, the engine and PTO automatically shut off. The engine also does not start if the parking brake is not engaged. The throttle must also be in the "fast" position before engaging the PTO.

Reverse Mowing

If you are trying to operate your LT1045's PTO while mowing in reverse, the throttle settings must be in the correct position. Start the engine as normal, according to instructions in the operator's manual. Put the key into the "reverse caution mode" position. Depress the "reverse push button" on the top right of the key switch module. When your mower is operating in reverse, always look over your shoulder while driving.

Engine Power

Your Cub Cadet LT1045's engine power affects the PTO's operation. Whenever the PTO is engaged to operate the blade, engine power transfers to the cutting deck. If engine power is low, the PTO is slow to engage or does not engage at all. Engine power is compromised by damaged spark plugs, contaminated fuel, choke control in the "on" position while operating or bad oil condition. Ensure these items are checked according to the manufacturer's recommended maintenance schedule.


The blade is connected to the PTO by washers and a hex nut. The blade rotates inside a protective undercarriage and discharges cut grass through a chute. If that chute is clogged from wet grass or dirt, clumping occurs and interrupts the blade's rotation. If there is rusting on the hardware or the PTO shaft, the blade may not spin consistently. Ensure the cutting deck is level so that the blade is not spinning too low or on dirt and objects. Do not cut on wet grass. If you clean the undercarriage with water, ensure the hardware is dry before storing your LT1045.