To keep an eye on the major lawn mower valve adjustment symptoms are necessary because, in any mechanical equipment, including lawnmowers, clearances, gaps, or valve adjustments are always essential parts that need little adjustments while being used, maintained, or repaired.
Valves are the doors to the engine for the intake and exhaust system in the lawnmower. And the valve clearances are the small gaps between the valve head and the rocker arm.
We are aiming to help you by providing you with the complete guide to notice, determine the lawn mower valve adjustment symptoms, and adjustments for your lawnmower to make its maintenance more manageable and profitable in time and budget.
Consequences of poor valve adjustment
The efficiency and performance of a lawnmower entirely rely on the maintenance of the intake and exhaust valves. Poor maintenance or bad adjustment may lead to a harmful impact on the lawnmower. It can cause:
- Rough idle engine running.
- Alignment and balancing issues.
- It can decrease the power and mileage.
- It can cause extreme heat damage to the engine.
- It can entirely damage the other valves.
Major Lawn Mower Valve Adjustment Symptoms
Valve gap may change with time and usage. Usage time is not the leading cause behind these changes, But the maintenance is the leading factor. And it also has some other symptoms beyond the maintenance part.
You can not, or not even the repairman, would know for sure without inspecting the valves, whether they need adjustments or not. But engines appear with some symptoms by which we came to know that valves need to be adjusted.
If your engine generates a loud tapping noise, or you are noticing some power loss in your lawnmower, then these are the signs of valves adjustment point. Let’s look at the top 5 lawn mower valve adjustment symptoms.
The major lawn mower valve adjustment symptoms can include:
- Hard to pull the starter cord.
- Hard starting.
- No Compression.
- Power loss with excessive fuel consumption.
- Noisy engine with rough running.
- Oil leaks.
Let’s take a brief look at these symptoms.
1. Hard to pull the starter cord – Major lawn mower valve adjustment symptoms
This is one of the most common and major lawn mower valve adjustment symptoms. A very familiar sign the lawnmowers show that is interlinked with the valve adjustment is the starter cord. The starter cord becomes hard to pull while starting the engine.
The cord becomes hard because of:
- Excessive cylinder compression.
- An increase in the valve gap.
Advance engines have compression release technology to open the valves early to release the compression of the engine and the cylinder.
2. Hard Starting
When the valve gaps are entirely misaligned, then it can cause a hard start engine.
Moreover, hard starting is the sign of an increase in the valve tappet or gap, which affects the whole mechanism behind the valve movement.
Hard starting further harms the head gasket.
3. No Compression or Starting issues
When the entire mechanism behind the valve movement becomes damaged, stuck, or misaligned, it causes starting issues, and the engine begins missing while starting.
Stuck valves are the result of lacking compression. You can fix the stuck valves by using a screwdriver to provide compression to the spring.
You can perform a compression test to check your engine life.
4. Power loss with excessive fuel consumption
Increased or decreased tappets can adversely affect the efficiency of the lawnmower by effecting its power. The lawnmower starts consuming more fuel or gas without providing proficient results.
It needs an adjustment to keep your lawnmower running and durable for a long time.
5. Noisy engine with rough running
You can also hear a tapping noise along with the power loss and excessive fuel usage because of an increase in the valve gap. Ignorance will lead the engine to permanent wear out.
When the inlet and exhaust valves are not supporting the engine to perform correctly, then the engine becomes off-balance and rough day by day, both in performance and sound.
Adjust the valves by using a feeler gauge and a wrench to help the engine in proper breathing to gain power while consuming less fuel.
Why the valve adjustment is important
Valve adjustment is vital to be maintained because:
- It can provide space for thermal expansion.
- It ensures the positive closing of the valves through spring support.
- Precise adjustment of valves provides the proper opening and closing times of valves.
- It improves engine mileage and performance.
- Poor valve adjustment affects fuel consumption.
In most of the engines, the function of rocker arms is to opens and shuts the inlet and outlet valves of the engine. Rocker arm and valve head are not directly linked or connected.
Increasing and decreasing the adjustments directly affects the opening and closing timing of inlet and outlet valves.
- Insufficient tappet causes early opening with late shutting to the valves of the engine.
- Extra tappet becomes the reason for the late opening and early closing of the valves.
Mostly, the general tappets, gaps, or valves adjustments range from 0.30mm to 1.5mm depending on air and exhaust valve manufacturing.
How to adjust Valve gaps – Fixing Major lawn mower valve adjustment symptoms
Once you know whether the tappets or the gaps are less or more, then it will be easy for you to increase or decrease them.
Although, the valve adjustment is a quite tricky and skillful session. But you can follow the mentioned steps to check out the valve adjustment:
- Remove the plug and turn off the fuel connection.
- While using a rag, remove the rocker cover.
- The rocker cover has a gasket. You can reuse or replace it according to the need.
- Rotate the engine by keeping an eye on both the valve and the compressing turns.
- By using turning blades, rotate the engine and keep noticing that the compression of valve springs.
- Make sure the straightness of the pushrods, otherwise make a replacement to avoid no start condition.
- Never try to remove pushrods for valve adjustments.
- Locate the intake and the exhaust valves.
- Rotate the engine clockwise by turning the blades.
Steps to Fix the Major Lawn Mower Valve Adjustment Symptoms
- Keep turning the blades and rotating the engine until the intake valve becomes open and fully compressed.
- Insert a round and unsharpened object into the plug hole against the piston. Rotate it clockwise again and keep noticing the point when the round object pushed out by the piston. When fully out, this is the Top Dead Center (TDC).
- Unloaded the valve springs by keep turning the object into the cylinder.
- It is the Power stroke point where the valve adjustment begins.
- Exhaust valve tappet increases with the heat. Valve clearances vary from model to model. Observe the valve gap, according to the manufacturer.
- Move the feeler gauge blade between the rocker arm and valve head to observe the resistance.
- Make sure the smooth movement of the feeler gauge between the valve head and the rocker arm to get a perfect valve adjustment; the gauge may not be too tight and also not very loose, i.e., between 0.30mm to 1.5mm.
- After getting a perfect valve adjustment, tighten the nut with the given torque.
- Keep the record for future adjustments.
Engine noise elimination is not only the benefit that is the result of properly adjusted valves, but the engine will also become efficient, smoother, and more responsive.
Moreover, proper adjustment can make the engine and the valves durable and efficient for a long time.
Always look out for lawn mower valve adjustment symptoms and take timely decisions to fix them. We hope this article will help you in observing, diagnosing the symptoms, and adjusting the valve gaps of your lawnmower on time.