By: Author John Cunningham. Published: 2021/07/04 at 6:59 am
In the beginning, I hated starting my power washer. We’d wrestle regularly until I learned to work with the machine. Now we’re the best of pals, and you are about to learn how you can be too.
The number one cause of a hard-to-pull power washer cord is the incorrect starting procedure. Follow these five steps to easily start a power washer:
- Set gas, choke and switch to “On”
- Connect garden hose
- Turn garden hose on
- Pull and hold lance trigger
- Pull start engine
In this post, you’ll learn why your pressure washer is too stiff to pull and what to can do to avoid the startup wrestle.
What Causes Stiff Starter Cord?
In my workshop, I see a ton of pressure washers in for repair. Many suffer from broken pull cords, and customers usually describe a similar type of fault – stiff or hard to crank over the motor, faulty pull cords, etc.
Of course, we know that’s not the problem. In the majority of cases, it’s an incorrect starting procedure which is the root cause of both the stiff pull cord and the disproportionate number of snapped pull cords.
So what’s going on? Why is it so stiff? The answer is simple, and the solution will seem obvious when you understand what’s actually going on. When you pull on a power washer pull cord, you aren’t just turning over the engine; you’re also turning over the pressure pump.
The stiffness you experience in the cord is a good thing; it means the pump is doing its job; it’s building pressure. Building pressure is tough work; the more you pull over the motor, the harder it is to pull the cord. An engine won’t start unless the engine turns over fast enough to fire the spark plug, which is about 300 rpm. Obviously, that’s not going to be possible with all that pressure built up inside the pump.
The solution is to release the pressure; to do so, simply pull and hold the lance trigger. And that’s what we’ll cover next.
The Correct Power Washer Starting Procedure
Before starting any engine, it’s a great practice to check the oil level and adjust it if necessary. I advise my customers to check the oil with every gas fill.
Pressure washers often lay up for long periods between uses; I also advise customers to use a gas stabilizer in the fuel. It helps keep the gas fresh and prevents carburetor issues. You can check out the gas stabilizer price and a video on correct use here on the “Power washer maintenance tools page.”
Here’s the correct starting procedure in a little more detail:
Pull the trigger and pull start
- Turn gas tap on – gas tap valve controls fuel flow to carburetor
- Turn choke on – required for cold starts
- Turn start switch to “On”
- Connect garden hose
- Turn garden hose “On”
- Pull and hold lance trigger – relieves pump pressure and also bleeds air from the pump
- Pull start engine
Diagnosing a Stiff Cord
If the above starting procedure didn’t help (didn’t relieve the stiffness), then it is very likely your machine does indeed have a mechanical issue.
A pressure washer is really a combination of two machines. A pump that builds pressure and an engine that drives the pump. In this section, we’ll quickly diagnose where the problem lies, in the engine or in the pump.
The diagnosis process is as follows:
Remove spark plug
Crank over the engine
- The pressure on the pull cord is relieved, and it’s likely there’s an issue with the engine.
- The pressure feels the same; the pump has likely failed.
In the next section, we’ll look at other causes of a stiff pull cord and what you can do about it.
Other Possible Causes of Stiff Cord
Here, I’ve listed many of the other issues related to a stiff pull cord. I’ve placed them in order of commonality.
Too Much Engine Oil
Overfilling with engine oil is so common, and the excess oil inside the motor leaves little room for the internals to move; the result is a slow or stiff pull cord.
If your oil level is high, but you didn’t overfill it, and your oil stinks of gas, suspect a hydro-locked engine. More on this below.
Hydro-locking is where a fluid (usually gas) fills the cylinder and causes the engine to lock up completely or results in a stiff pull cord. Hydro locking typically happens when a wash is turned over on its side or when the carburetor float valve (aka needle) wears out and leaks, which allows gas to flood the engine.
Common symptoms are a smell of gas, gas leaks, high oil levels, lots of smoke If the engine starts), and a fouled spark plug.
The fix – replace the carburetor float valve, but you’ll need to change that oil too. Best to turn the gas tap off when the wash is not in use; this relieves pressure on the float needle.
Compression Release Valve
An engine needs compression to fire and produce power; compression in itself results in a stiff pull cord, and so to relieve the difficulty, manufacturers employ a simple component known as a compression release valve.
As its name suggests, the release valve releases compression from the cylinder. It does so by opening the exhaust valve, just a touch while engine cranking.
When the engine starts, the release valve is redundant. Release valves do give trouble and may result in a stiff pull cord; customers commonly describe the cord as snapping from their hands.
The fix – replace the release valve. Some engines are a gift to work on; replacing the valve is a thirty-minute job (Honda). Other engines will require a full strip down to access the valve.
Valve Train Issue
A valve that doesn’t open in time or simply doesn’t open will cause excessive engine compression. And as you’ve already heard, engine compression may result in a stiff pull cord.
A valve that doesn’t open in time is likely a matter of adjusting the valves; it’s a pretty common maintenance task. You can check it out here. This post covers a mower engine, but the process is identical “Adjusting valve lash” or check out the video here.
A valve that doesn’t open is a more serious issue. It may mean a rocker has broken or a push rod has bent, depending on the engine type.
It may also mean a camshaft is faulty, and while this isn’t a hugely common issue it does happen.
A shear key is a small metal key and has two functions. It aligns the flywheel and crankshaft, and its second and equally important function is to shear when called upon.
When an engine comes to a sudden stop (e.g., pump seizure) and because the flywheel carries mass, it’s inclined to keep turning. In fact, the flywheel carries sufficient energy to twist and destroy the crankshaft. It’s just prior to this moment that the shear key breaks and decouples the crankshaft from the flywheel.
When the shear key decouples, the timing of the engine is off and will cause a stiff pull cord. As said, a power washer’s broken shear key is not hugely common, but still a possibility.
Small engine failure is not that common in a well-maintained motor. Indeed, even a poorly maintained motor is surprisingly durable.
Let them run out of oil, though, and it’s over; lack of oil will allow internal components to get so hot they fuse together. However, before that happens, the engine begins to get tight, and that will result in a stiff cord.
Oil conditions will tell you a lot about what’s going on. Very low, or no oil, fear the worst.
Pumps work hard and do fail. When they fail, they often seize, which will make the pull cord hard or really stiff to pull. Many pumps are oil for life and don’t require maintenance, so don’t feel bad about it.
However, generally, if a pump has an oil fill and drain hole, it means the oil should be changed. On pumps that do allow an oil change, change about every 100 hours of operation.
For parts and tools, check out “Pressure washer maintenance tools page.”
You may also find “Pressure washer troubleshooting page” useful.
Other Pressure Washer Posts:
- About the Author
- Latest Posts
John Cunningham is an Automotive Technician and writer at Lawnmowerfixed.com.
He’s been a mechanic for over twenty-five years and shares his know-how and hands-on experience in our DIY repair guides.
Johns’s fluff-free How-to guides help homeowners fix lawnmowers, tractor mowers, chainsaws, leaf blowers, power washers, generators, snow blowers, and more.