How to Unseize a Small Engine: Small Engine Guide

A seized small engine can be rather hard to identify at the first look, as the exterior may not tell the story. But when you see the engine housing seems to change color, or there is a smell of something burning, then this could be the seizure of your small engine. 

A crankshaft - a rotating shaft that turns the motions of the small engine piston into spinning motion, can also tell if the engine is seized or not. If you try to move or turn the crankshaft manually, you may feel that it is extremely difficult and somewhat impossible to move. This can also be the sign of a seized small engine.

Another possible sign for a seized small engine is that you find a lot of metal shavings in the oil. Overtime, all small engine parts wear and tear tinily, piece by piece. This is where the small engine oil comes in handy. If the engine oil is too old and not getting renewed, there will be an excessive amount of metal shavings moving around the engine. This causes your engine's components to rub one against another much more often than needed - which leads to the damage of your small engine. In this case, the size, amount and type of metal shavings will determine how severe the issue is.

If you found broken parts inside your small engine like the piston, piston rings, bearings, scored cylinder walls, then this is also a sign for your seized small engine.   

A seized small engine can be really challenging to fix as you need to check and look into many problems of your small engine to get to the right cause of the engine. We can guide you for an in-depth preparation, but that may be a little bit unrealistic for you to buy an entire new set of tools for your engine. The list below is the tools you need to fix a seized small engine.

First, let’s look into the basic tools you need: 

• Socket Set: You should have a set of sockets with a ratchet handle. If you have a set, they commonly cover common sizes, and the parts of your engine would surely match.
• Wrenches: A set of combination wrenches (open-end and box-end).
• Screwdrivers: A set including both flathead and Phillips.
• Pliers: Needle-nose and slip-joint pliers.
• Spark Plug Wrench: For removing the spark plug.

Second, prepare some specific tools for unseizing such as:

• Penetrating Oil: Such as WD-40 or PB Blaster.
• Rubber Mallet or Small Hammer: For gentle tapping if necessary.
• Feeler Gauge: To measure clearances and gaps.

Third, get yourself some cleaning and inspection Tools:

• Wire Brush: For cleaning parts.
• Degreaser: To clean oily and greasy parts.
• Sandpaper or Emery Cloth: For smoothing rough surfaces.

We highly recommend you also prepare some disassembly tools:

• Pry Bars: For separating parts that are stuck together.
• Torque Wrench: To ensure bolts are tightened to the correct specification.

And don’t forget some essential replacement parts and supplies:

• New Gaskets: To replace any that were removed.
• Engine Oil: Fresh oil for reassembly and initial startup.
• Lubricants: Penetrating oil and engine assembly lube

The following steps is what you should do to fix a seized small engine:

Step 1: Initial Diagnosis: 

Use the spark plug wrench and also the flashlight if it is too dark to inspect the cylinder through the spark plug hole. 

During this process, you should try to take notice of the spark plug conditions - they could be either wet, dry, fouled or cleaned correctly. If you find that your spark plug is fouled, the issue can be the oil or the fuel of your engine. 

In this step, you are also required to pay attention to the damage inside the cylinder. If you find that there is carbon buildup or a lot of debris inside the cylinder, this can be the sign of poor combustion for your engine. It is also the result of other objects getting into the cylinder.

Another thing to take note of here is how you remove the spark plug. If you find it too hard to move, then it is a sign of rust or even carbon buildup.

Step 2: Remove the Oil

For this step, you need a wrench set, an oil pan to remove the oil out of the engine. 

The key for this step is to drain the oil out of the engine and inspect it for metal shavings or debris. If you find metal shavings in the oil, then this can be the cause for wear and damage. If you see that the oil is milky like it is being mixed by water, then the oil may have been contaminated. It’s time to replace your small engine oil.

Step 3: Check, Inspect and Replace

First, you need to disassemble the engine. Use the socket set, wrenches, and screwdrivers to take apart the engine, starting with the flywheel and working inward. After that, you should start to inspect parts. Check the piston, cylinder walls, crankshaft, and bearings for damage.

If you find the engine parts getting dirty, it’s time to clean them.  Use the wire brush, degreaser, and sandpaper to clean all parts thoroughly.

If you find any damaged parts, it’s now time to replace them. Install new pistons, rings, bearings, or other components if the current parts can not work effectively or have the signs of broken.

Step 4: Reassemble and Test The Engine 

Carefully put the engine back together using new gaskets and torque all bolts to the manufacturer’s specifications. 

At this point, you should also test the compression level of your small engine. Don’t forget to test the compression level to ensure the engine has proper compression before starting.

Step 5: Test the engine

Start the engine and check for any other issues.

Your small engine works, and its parts and components eventually wear off, which possibly leads to small engine seizure. There are ways to stop that from happening, and these are some advice we have for you:

Do not forget about regular maintenance. Always perform regular maintenance on your engine, including oil changes, air filter replacements, and spark plug checks.

And remember, store the engine correctly. Store the engine in a clean, dry place. If you want to store it for a long time, use fuel stabilizer to keep the fuel quality at its best. 

If you are a person who frequently updates the engine parts, then always use high-quality replacement parts and lubricants as specified by the manufacturer.

A seized engine can indicate issues such as overheating, poor maintenance, inadequate lubrication, or underlying mechanical failures that need to be addressed. Sometimes, if the cause is not too big of a deal, we highly recommend you to fix it on your own so that you can save the engine and a lot of money for yourself. And remember, always do the maintenance work so that your small engine won’t get seized.

1. What causes a small engine to seize?

A small engine can seize due to lack of lubrication, overheating, running out of oil, or internal damage such as a broken piston or crankshaft.

2. What tools do I need to unseize a small engine?

Basic tools include a socket set, wrenches, screwdrivers, pliers, a hammer, feeler gauge, compression tester, torque wrench, spark plug wrench, and an inspection camera.

3. Can I unseize an engine without disassembling it?

Sometimes, using penetrating oil or a mix of automatic transmission fluid and acetone poured into the spark plug hole and letting it sit can help. However, severe seizures typically require disassembly.

4. Is it worth fixing a seized small engine, or should I replace it?

It depends on the extent of the damage and the cost of repairs versus replacement. For minor seizures, it’s often worth fixing. Severe internal damage might make replacement a more cost-effective option.

5.  How can I prevent my small engine from seizing in the future?

Regular maintenance, such as checking and changing oil, keeping the engine clean, ensuring proper lubrication, and not overworking the engine, can prevent seizures.