How to Repair a Seized Lawn Mower Engine

Dealing with a seized lawn mower engine can be frustrating, especially if your mower has been properly maintained. However, in some cases, you may be able to revive it with a little troubleshooting and effort. This article will guide you through the process of repairing a seized lawn mower engine and discuss potential alternatives if repair isn't feasible.

Common Causes of a Seized Lawn Mower Engine

A seizing engine occurs when the moving parts in the engine stop moving due to a lack of lubrication or rust. This can happen for various reasons, such as improper storage or a lack of maintenance. For instance, when moving to a new location, several months ago, the movers drained the gas and oil from our Ariens lawnmower, leaving it vulnerable to seizing.

Determining the Cause and Capacity for Repair

First, determine whether the cause of the seizure is due to lack of oil or if the parts are rusted or seized due to extended exposure to the elements.

Check if the mower has been sitting outside for a prolonged period; this can increase the likelihood of rust and seizing.

Verify if the mower has been recently used. If it has, the engine may be seized from overheating or other mechanical issues.

Assess your own mechanical skills and whether you have a workspace to handle the repair.

Inspect the internal parts of the engine, particularly the bore, if it appears to be scored.

Steps to Revive a Seized Lawn Mower Engine

If it seems the engine is seized due to rust or lack of lubrication, you can try the following steps:

Remove the engine head to inspect the bore. Light rust may be removed using penetrating oil and gently knocking the piston down with a wooden block.

For a 4-stroke engine, valve seats may need to be recut and valve clearances reset. This requires specialized knowledge and tools, so consulting a small engine specialist may be necessary.

If the bore is seriously scored, the cost of a replacement engine may be more feasible than repairing it. Consult a small engine specialist for a quote.

When Repair Isn't Feasible

If the engine is severely seized, or the cost of repair is too high, you may need to consider buying a new mower. Buying a used mower with a working engine may be a more economical solution, especially if it has been returned by an unsatisfied buyer. I once found a returned Ariens mower at K-Mart for only $80 and managed to swap it out and get it running again, extending the life of the mower for an additional 15 years.

Conclusion

While repairing a seized lawn mower engine can be challenging, it can also save you money and keep your mower in working order. By carefully assessing the cause of the seizure and taking the necessary steps to repair or replace the engine, you can ensure your mower remains a valuable asset in your upkeep routine.