How to Break in a Small Engine

When you get a new chainsaw, cut off saw, lawn mower, or other small engine powered piece of equipment, it's critical to break the engine in so it runs properly. The reason behind this is that you want to heat the engine up to seal the piston rings to the cylinder wall, which will minimize friction in the cylinder and prevent oil from gathering in the cylinder wall. For this reason, it's also important to break in your engine again if you replace the piston rings.

So how do you break a small engine in exactly?

1. Fill the engine with the recommended oil

Your owner's manual will specify what type of oil to put in your power equipment. Be sure to regularly change your oil and make sure that there is enough in the engine at all times. For two-stroke engines, we recommend using Lucas 2-Cycle Semi-Synthetic Oil. Lucas oil is formulated with a blend of mineral oil, synthetic oil, and low ash additives that allows fuel to burn thoroughly for smoother engine operation.

2. Idle the saw for 5 minutes

Start up your engine like normal and let it run idle for a few minutes to get the engine warmed up. You can rev the engine a bit to keep it from shutting down, but you want to make sure the engine is warmed up before running it normally.

3. Run the engine as normal, but not at full throttle

For at least 5 hours, you will want to run your engine as normal but don't hit full throttle just yet. If you do run your engine at full throttle, you risk deformation of the cylinder bores. After this period, it's okay to run the engine at full throttle when it has a load. Many chainsaw operators recommend only running the saw at full throttle when the saw is in the cut, for example.

4. Change the oil

Some chainsaw operators and technicians recommend changing the oil in a new saw after an hour of operation. Most new saw owner's manuals will tell you to change the oil after 5 hours of operation. If you want to be extra safe, you can do both, but generally speaking, changing your oil after 5 hours is sufficient. The reason for this oil change is to remove any tiny debris that has broken away from the engine components and remained trapped in the oil.

Once the saws oil has been changed after the 5 hour threshold, your saw is ready to use regularly and at full throttle. Many technicians and small engine experts have their own methods of breaking in their engines. Please leave your comments with your own method!

HLSupply provides small engine parts for chainsaws, mowers, cut off saws, and more. Visit our store for our complete selection of parts including cylinders & piston rings.