Perhaps you’ve enjoyed many long, hard hours on your mower and it’s finally time to replace the engine. Or perhaps something unfortunate happened to your mower’s engine that caused it to be damaged beyond repair. It’s actually not unusual to replace or rebuild the engine several times in the entire life of the mower, since we aim to make its core so durable as to last two to three times the life of the engine.
It’s important to remember that most lawn mower manufacturers cannot sell the engine manufacturer’s service parts, service the engine warranty, or sell replacement engines. Work closely with an authorized engine dealer when updating your mower.
You have several options:
Rebuild the engine
Generally, the cost of many hours of labor to rebuild the engine and the risk that something may go wrong make rebuilding not worth it. The exception is when you’re confident that most of the engine is in great shape and the rebuild can be isolated to a specific area. For example, the cylinder heads are worn out.
Install a short block
A short block is a fully assembled and sealed engine block with all the critical moving parts inside. Most engine companies offer this option, which is cheaper than a new engine. However, you will have to pay for the labor to move all the external engine parts (i.e. flywheel, starter, magneto, carburetor, manifold, governor) over to the new engine.
Replace the entire mower engine with exactly the same model
This is usually the most successful and straightforward option. The engine may cost more in some cases, but you’re not gambling that additional problems might be found on the old engine parts or that it takes longer than expected.
Repower the mower with a different engine
Although this is commonly and successfully done, we have no way to know what engine is being installed, so we can’t provide much input or endorse the engine application. The upside is that it’s often possible to shop around for a cheaper engine, but you might end up having to rewire something or cobble together a muffler.
Sell the mower without the engine running
Sometimes there are folks looking for a deal that are not intimidated by the thought of having the engine replaced. It’s great if you can find handy people like this in your area on the lookout for commercial mowing equipment.
Since it’s costly to repower your mower, what can you do to get more life from your engine?
- Keep the oil clean and follow the engine manufacturer’s recommendations for what oil to use in your area of the country. If you’re not sure, talk to your local Wright dealer.
- Keep the air cleaner clean. Don’t let dust fall into the intake when replacing or cleaning the filter. Although it seems to work well, DO NOT use compressed air to clean out a filter—this will cause damage and let in small grit.
- Prevent grass from building up on the fins, which can cause the engine to run hot.
Premature engine loss is a very sad thing. Plugged fins will cause the engine to overheat and most engine manufacturers will not want to cover this under warranty. Sometimes the issue is caused by a broken connecting rod from welding on the crankshaft. If the engine is run hot or the oil is dirty, the connecting rod may wear and knock but it will only weld to the crankshaft from receiving zero lubrication. Most manufacturers will not warrant metal transfer (aluminum welded to the crankshaft). To avoid this, always keep your oil topped off and do not operate the engine at angles over 20 deg.
With these considerations in mind, your mower engine update will go smoothly and you’ll be back mowing lawns in no time.