13 Causes a Cub Cadet to Slow Down and Lose Power

Cub Cadet Mower With Expired Gasoline

A Cub Cadet mower that has been running on old gas will perform poorly. This is due to the rapid decomposition of gasoline after just 30 days.

Gummy deposits caused by ethanol’s attraction of moisture in the fuel system reduce gasoline delivery. When the engine isn’t supplied with enough fuel, performance suffers.

Remove the old gas from your Cub Cadet mower’s tank and replace it with new gas. All Cub Cadet mowers that run on gas should only be filled with unleaded gasoline that has an octane rating of 87 or above and contains no more than 10% ethanol.

Even though modern Cub Cadet mowers have 4-cycle engines that run on unleaded gas, older models with 2-cycle motors are still in use.

The fuel tank of a 2-cycle engine must contain both gasoline and oil. Here you can learn more about the many fuel options for your Cub Cadet mower.

Fuel additives, such as Sea Foam Motor Treatment, can help with gas stabilization, moisture reduction, and fuel system cleaning.

Sea Foam is also useful when you have more gas than you can use in a month’s time. When I fill up the tank, I always include some Sea Foam to keep the fuel system and engine protected.

This tutorial will explain in detail why I think Sea Foam is great.

Cub Cadet Lawnmower Fuel Filter Clogged

To prevent contaminants from contaminating the fuel system, a fuel filter cleans the fuel as it exits the fuel tank. If you don’t replace your filter on a regular basis, it will get clogged up and not let any fuel through.

When maintaining your Cub Cadet mower, it’s recommended that you change the fuel filter once a year.

This filter is a low-cost component that, if it fails to strain dirt effectively, can lead to problems with the fuel supply and serious engine damage.

In order to change the filter, the fuel supply must be cut off. This can be done with the mower’s fuel shut-off valve or, if your mower doesn’t have one, with fuel pinch-off pliers. Remove the old filter from the gasoline lines and replace it with a new one.

Most inline filters will have an arrow pointing in a specific direction. The arrow on the filter should face the direction of gasoline flow while being installed. The arrow should be aimed at the carburetor, not the gas tank.

A Cub Cadet Lawnmower with a Blocked Fuel Line

The gasoline lines can become clogged with the sticky deposits caused by using old gas.

If your Cub Cadet mower isn’t getting gas, you can check for a blockage by turning off the fuel supply, cutting off a part of the fuel pipe, and putting the cut end in a container. Turn on the fuel supply and make sure it is able to flow freely from the fuel line.

If you discover a clog in the fuel line, you should turn off the mower’s fuel supply and disconnect the affected piece of the fuel line. Clean the line by spraying carburetor cleaner.

The purpose of this is to break up the ice. To remove the blockage, pressurized air should be blown through the line.

If you can’t get the obstruction out or the gasoline line is dry and damaged, you should get a new one that’s the same size.

A Cub Cadet Lawnmower with a Filthy Carburetor

The carburetor on your mower is crucial to its operation. It controls how much air and fuel are injected into the cylinder to ensure proper combustion.

Old gasoline’s byproducts can build up in the carburetor and render it unable to supply the engine with the fuel it needs to function. If the carburetor on your Cub Cadet mower gets dirty, it might cause a lack of power.

If fuel isn’t getting to the cylinder, it may be time to clean the carburetor. First, take out the air filter and spray some carburetor cleaner into the air intake before you start dismantling the carburetor.

Check the engine’s viability by starting it. If your automobile starts but dies quickly, it needs a carburetor cleaning. If you want detailed instructions on how to clean the carburetor on your Cub Cadet, read this article.

Cub Cadet Spark Plug Problem

A loss of power may arise from a fouled spark plug causing an intermittent spark. Carbon, dirt, and oil accumulation on the spark plug’s tip are all things to look out for.

If you detect a damaged or filthy spark plug, you should get a new one to make sure the mower is always working smoothly.

If it’s just dirty and not too dark in color, you could try cleaning it with a wire brush and putting it to good use again.

Cub Cadet Lawnmower Has Low Engine Oil

The power of your Cub Cadet mower will diminish if the oil level in the crankcase gets too low. Inadequate oil added to the crankcase during the previous oil change may be the cause of your current oil shortage.

It could also be the result of using the incorrect oil viscosity or an oil leak in the engine.

Mowing when the oil level is low is dangerous. If you do and it’s not noticed right away, you could end up spending a lot of money fixing the engine or possibly having to replace it.

Lubrication of the engine’s interior components is impossible without engine oil. Lack of lubrication causes friction between the moving parts, which in turn generates a great deal of heat.

This can lead to your Cub Cadet mower overheating, which in turn can cause the oil to burn and the parts to melt.

As a safety measure, you should always check the engine oil level of your Cub Cadet mower before starting it up.

I know it’s an extra chore on your already full plate, but it won’t take long and will help you prevent major issues like oil leaks and engine breakdowns.

You can see how much oil is in your engine by taking out the dipstick and wiping it with a dry cloth. Put the dipstick back in its position and take it out. See if the oil has run out. When checking the oil, make sure the dipstick reads full.

If not, fill it up with fresh engine oil. Don’t cram too much in there or you’ll have even more issues.

After filling the engine to the maximum level, if issues persist, you should have it checked by a qualified small engine repair.

It’s possible that a lack of engine oil led to internal damage that new oil wouldn’t be able to cure.

Overfilling the Cub Cadet Lawnmower’s Gas Tank

If you add too much oil to the crankcase, your engine will start smoking. Too much oil in the engine causes pressure to build, which can force oil through the valves and into the cylinder.

If this occurs, the cylinder will begin to exude a bluish-white smoke as the oil burns.

This dense plume of smoke may clog your air filter, preventing your engine from receiving the clean air it requires to function properly. You should clean or replace your spark plugs and air filter as needed.

If you keep your Cub Cadet mower running after discovering that you’ve added too much oil, you risk damaging the seals, hydrolocking the engine, and bending the piston rod.

Take Out Some of the Engine Oil

The oil can be drained from the engine by releasing the drain plug and then immediately re-tightening it. A turkey baster or oil evacuator can also be used to drain oil from the oil filter or the oil fill area.

Cub Cadet Mower with a Filthy Engine Cooling System

Air is used to cool the engine. The cylinder head and engine block are both exposed to airflow.

If grass clippings and mud become stuck in the cooling fins, airflow around the engine will be reduced, so keep them clean. Fix the broken cooling fins.

Cleaning the engine shroud and air intake areas is as important as keeping the cooling fins clear of debris to prevent the engine from overheating and losing power.

A Cub Cadet Lawnmower with Blocked Air Vents

To avoid the engine overheating and losing power, proper cooling is essential. Make sure your engine has adequate air flow by clearing the area around it of any debris, including grass clippings and dirt.

Clear off the clutter from underneath your engine shroud. Check that the heat shield is properly fastened.

Cub Cadet Mower Fast Ground Speed

It’s understandable to want to get the mowing done as soon as possible so you can kick back and relax for the day, but you could be causing your Cub Cadet mower to overheat in the process.

When mowing thick, wet, or tall grass, going at a fast speed might put extra strain on your mower.

To reduce wear and tear on your Cub Cadet mower, adjust the pace of operation based on the terrain you’re cutting. This involves reducing speed when cutting grass on a slope.

Using a Cub Cadet Mower to Cut Wet or Tall Grass

If the grass is moist or damp, don’t cut it. The engine has to work harder through wet grass.

It’s more likely to clump together and become stuck on the mower deck’s underside. Mowing your lawn when the grass is dry can give you the best results.

Cutting your grass on a regular basis will help keep it at a manageable length. If the grass grows too long for your mower, it may become stuck while trying to cut it.

Despite your best efforts, there will inevitably be periods when your lawn becomes unmanageably long.

For the best results when cutting tall grass, mow it twice or even three times. To accomplish this, raise the cutting height of the mower deck for the initial cut and then decrease it for subsequent cuts.

Cub Cadet Mower with a Blocked Deck

To prevent the engine from overheating and losing power, the space under the mower deck must be kept clean and clear at all times.

Cub Cadet mower blades should have enough of room to spin and move underneath the deck when in use.

When the engine has to work harder to turn the blades through debris on a clogged mower deck, it takes a toll on the machine. Remove material from the mower deck on a regular basis by scraping it.

This is beneficial for both the engine and the cutting performance of your Cub Cadet mower.

Cub Cadet Lawnmower with Dull Blades

The issue of a blocked deck is exacerbated by dull mower blades. When worn blades are added to a deck that is already losing power due to plugging, the engine must work harder to turn the blades.

Make sure your blades are sharp or get new ones if they are dull. The inspection and honing of blades is covered in further detail here.

Is Your Cub Cadet Lawnmower Still Giving You Trouble?

If your Cub Cadet problem still persists after trying these suggestions, or if you’re having a different issue with your mower altogether, I recommend checking out my guide, which details the most frequent issues and how to fix them. Normal Issues with a Cub Cadet.

Find out why your Cub Cadet is having problems like it won’t start, won’t cut properly, vibrates too much, or even starts smoking. I provide answers and resources for further study.