If you own a house in the suburbs, then there’s a good chance that it comes with its own front lawn, complete with a garden for you to grow and maintain. And if you love gardening and the thought of making your lawn stand out, it quickly becomes more than just a simple hobby.
It soon becomes a responsibility that you must carry out to ensure your house looks its best at all times. And to do that, one of the most important tools you need in your arsenal is a lawnmower.
While back in the day, a basic manual mower might be enough to get the job done, these days, riding mowers offer a much better value for the price. Now, I’m sure you’re aware that the engines that your lawnmower uses differ from the main manufacturer of the lawnmower.
For example, you might want to get a John Deere lawnmower for your projects, but the engines inside the vehicle might vary between Briggs and Stratton, Kawasaki, or even Yanmar.
Kawasaki, in particular, has always been one of my favorite engine manufacturers. There’s just something about their engines that brings out the best in any utility tractor. It offers amazing power and also doesn’t cost too much. In residential-style lawnmowers, the most common engine used is the Kawasaki FR615V.
In this article, I will explore some of the common issues you might face with your Kawasaki FR615V engine and help you troubleshoot these problems with minimal hassle. So, let’s get started.

Common Issues With The Kawasaki FR651V And How To Fix Them
The Kawasaki FR651V is a pretty reliable engine boasting around 21.5 HP engine power at 3600 RPM. However, in lawnmowers, many issues can come up suddenly. And unless you know what’s causing the problem, it can quickly escalate.
So, whenever you notice your engine showings signs of trouble, it’s best to deal with it right away. There are a couple of common problems that I have seen people struggle with in this particular engine. So, let’s address these problems and help you figure out how you can deal with them easily.
1. Engine Does Not Start

If the Kawasaki engine in your tractor refuses to crank, I understand how that can be a cause for concern for a casual owner. But don’t worry – this is a pretty common problem in most engines.
And in most cases, this issue comes up because of a fault in the fuel system. The first thing to do here is to check the gasoline tank and see if there is enough fuel. Using the wrong grade of gasoline can also lead to this issue as well.
Another possibility here is that the gasoline grade is correct, but the condition of the fuel deteriorated, which is preventing the engine from starting up. So, you need to take proper steps depending on the situation.
If the tank is empty or the fuel level is low, simply refill the tank. However, if the gasoline grade is wrong or if the fuel is stale, you want to drain the tank, clean it up, and pour a fresh batch of fuel. After that, check to see if your engine starts up.
If the engine is still not starting, then you need to inspect the fuel filter and the spark plug. A dirty or clogged filter can prevent the engine from getting enough fuel, while a faulty ignition spark can cause the engine to freeze. If the spark plug is the problem here, then you need to replace it.
All these steps should allow your engine to start up. If it still doesn’t turn on, check the carburetor, and adjust the float level. You should also clean the carburetor if it’s too dirty.
2. Engine Is Overheating

Another issue that often comes up in this engine is overheating. And naturally, this is a big problem. If an engine is allowed to overheat regularly, it can quickly escalate into complete engine failure.
So, you need to figure out what’s causing the engine to heat up and take proper steps to prevent it. The most obvious reason behind the issue is excessive load on the engine. And if you suddenly notice an overheating issue in the engine, the first thing you should do is try reducing the load.
Pushing the engine beyond its capabilities is never a good idea. If you’re lucky, this should immediately fix the problem. However, sometimes, engine load has nothing to do with this issue. In some cases, the problem comes up because of a faulty or compromised cooling system in your lawnmower.
So that’s what you want to check next. Inspect the air inlets and vents in your machine and make sure there are no blockages in the airflow. You also need to inspect the level of engine oil.
The primary purpose of engine oil is to keep the engine lubricated and cool. And if the level gets too low, it can lead to heat buildup in the engine. If the oil level is low, make sure you top it off with fresh oil.
Lastly, adjust the low idle speed in the carburetor. If the idle speed is set too high, it can put a lot of unnecessary stress on the engine, which can lead to this sort of unusual heat buildup in the engine.
3. Engine Does Not Idle

I know that it can be annoying if your engine shuts down the moment you put it into idle. But thankfully, this is a pretty simple and straightforward issue to diagnose. This sort of issue usually come up because of a faulty spark plug or when the spark plug gap is not set properly.
So firstly, check the spark plug for any signs of damage. A quick visual inspection should tell you whether it’s working or not. If the spark plug is fine, then reset the spark plug and ignition gap.
Also, make sure the spark plug is seated tightly in its slot. However, if the spark plug is damaged, make sure you replace it right away. And when installing the new plug, you need to carefully check the gap and seating of the component.
4. Underperforming Engine
If you suddenly notice that your lawnmower’s Kawasaki engine is performing below its usual standards, it’s not a good idea to ignore it. This can mean a lot of things, and you need to narrow it down to its root cause if you want to fix the problem and restore your vehicle’s performance.
The first reason behind an underperforming engine is overheating. And I have already discussed what to do if that happens. However, an excessive level of engine oil can also cause your engine to underperform.
When the engine level is too high, it can prevent the engine from heating up properly to do its job. In that situation, you need to drain the excessive engine oil. You should also take a quick look at the fuel pump and make sure it’s pumping the proper amount of fuel to the engine.
If the engine is getting starved for fuel, this can explain why it’s performing poorly. You might need to replace or repair the pump if that’s the problem. If the problem persists, there’s a chance that the Governor in your lawnmower is faulty.
Replace or repair the Governor and also adjust the float level in the carburetor. One of these solutions should help restore your engine’s performance.
5. Black Smoke Coming Out Of The Exhaust
Some people also complain that their lawnmower emits black smoke from the exhaust when they operate it. And since the smoke is produced by the engine, this means it’s a problem in the engine that you need to solve.
Now the most obvious reason behind it is that the air filter is dirty or soaked with oil. Cleaning the filter can quickly solve the problem. However, if that doesn’t fix things, you need to check the choke. A partially engaged choke will result in black smoke, so if the choke does not engage fully, you need to replace or repair it.
Another reason behind the problem is a faulty carburetor needle valve or a loose seat. So, inspect these components and replace them immediately if they look damaged.
Final Thoughts
Despite a few minor hiccups, the Kawasaki FR651V still manages to be one of the most popular engine models out there, especially for residential lawnmowers. While its power might seem subpar for commercial lawnmowers, in a domestic setting, this beast of an engine can truly shine.
Of course, maintenance is the key if you don’t want to deal with any sudden issues popping up in your engine. Regularly checking the fuel and cooling system, along with cleaning up the carburetor and other components, can help prevent most of the issues that I talked about here.
I hope my thorough discussion of the common Kawasaki FR651V problems could help you troubleshoot your engine with minimal effort. Good luck!