Why is My Generator Hard to Pull Start?
- BY BISON
Table of Contents
Pull cord hard to pull when trying to start a generator during a power outage, that’s not the dictionary definition of a good time.
But unfortunately, we have encountered a generator that is hard to pull start manually. Thankfully, it’s usually easy to fix if you’ve been taking care of your equipment.
Generally, the portable generator will have difficulty starting due to a hydraulic lock in the cylinder, a recoil start component failure, a damaged flywheel or flywheel key, a stuck piston, or a damaged compression release.
We’ve discussed these five reasons and what you can do to fix the problem. We numbered them in the order we used when trying to diagnose why the generator is hard to pull start. It’s best to first start with the most straightforward explanation and work up to generators as needed.
Let’s get started!
How does the starter rope on a generator work?
Before trying to fix something, it’s best to understand how it works. So we’ll briefly explain how a starter rope starts a generator and how to use it without damaging the portable generator or kickstart components.
Most recoil starter or pull starter systems comprise a rope with a handle attached to one end. The end of the cord opposite the handle is coiled inside a spool and held under tension by another spool with a spring. These two interconnected spools are called the spool assembly and are connected at one end to the crankshaft by a ratchet mechanism called a flywheel clutch.
Pulling the handle connected to the starter rope, the rope uncoils, tensions the spring, and engages the clutch, turning or rotating the crankshaft to start the engine. When the handle is released, the spring in the outer reel releases the tension and coils up the cord, ready for another start attempt.
There are good reasons why the ropes are not attached directly to the crankshaft. When the engine starts, the crankshaft will continue to spin, causing the rope to bounce violently enough to injure or damage anything attached to the other end.
Older pull-start systems consisted of a cord with a handle attached to one end and the other coiled around a notched reel attached directly to the crankshaft. When you pull on the rope, it disengages from the spool while spinning the crankshaft. If the engine does not start, the starter rope must be rewound to the wheel and pulled again.
Why is the generator hard to pull start, and how to fix it
Now that we know how recoil starter components work, it’s easier to understand where problems can arise and how to fix generator starter. Below is a list of common faults with rope start systems and methods on how to fix them. We’ll also discuss precautions you can take to make sure you don’t have to deal with stiff gas generator ropes in an emergency.
hydro lock
If you find it challenging to pull the recoil starter cord on your gas generator, the first thing we would check is to see if you have a hydro lock. Hydrolock means liquid on top of the piston in the combustion chamber.
Pistons can’t compress liquids, but they can compress gasses, so if you have oil, gasoline, or water on top of the piston, then you won’t be able to pull the recoil starter cord because you can’t overcome the laws of physics. If you decided to compress fluid in a sealed combustion chamber, the cords or tendons in your arms and shoulders would snap!
You need first to remove the rubber boot stuck on the spark plug, then use a spark plug removal tool or a deep well socket and ratchet to easily remove the spark plug. Then use a flashlight to see if there is liquid in the combustion chamber.
Carefully dip in the liquid using thin dowels and a clean, taped rag if you see fluid. Knowing whether it’s water, gas, or oil can help you diagnose precisely what’s causing the problem.
With the spark plugs removed and the generator outside, keep your face away from the spark plug hole and slowly and gently pull on the starter wire.
Are things getting easier?
If yes, then you have a hydro lock.
If you still can’t pull, continue to the next section. Continue with this section if you can.
If you can pull the wire lightly now, make sure your generator is outside and protect your face while you pull the wire a few times quickly to flush the cylinder. When we say flush out, we mean all the liquid contents are ejected from the spark plug hole.
Having done this, you can now put the spark plugs back in, put the boots back on, and your generator should start (at least temporarily).
Let’s take a quick look at why.
If your diesel generator is tipped over or left in a hard corner for too long, oil can seep through the piston rings and sit on top of the piston; a water lock can occur. If the rag you dipped has oil on the end, you only need to rinse it as above. Of course, check the oil level first.
Hydrolock can also occur due to gas if the floating needle valve in the carburetor is not working correctly and is not preventing gasoline from entering the carburetor bowl. This gasoline will rush to the top of the carburetor and exit the throat through the air filter side or back into the combustion chamber, depending on the generator’s angle during storage.
If you have gasoline on your rag, you must clean out the carburetor as it will continue to flood. You’ll also need to change the oil, as gasoline will undoubtedly seep into the crankcase as it works between the pistons and cylinders.
If you leave your diesel generator outside, the water lock can also be caused by water in the combustion chamber, which can get in through the exhaust pipe if it rains hard enough. This water can also cause rust, which can also seize your pistons, but we’ll talk about that later.
If water is on the rag, you soak the combustion chamber. Then you can keep running it after rinsing it, as we mentioned before, and after changing the oil, as the water may mix with it.
Recoil starter assembly
If the hydro lock isn’t your problem, we will check to see if it’s just the recoil starter rope wire. Occasionally, the cord may wrap around itself and get stuck in it.
Broken/cracked flywheel or flywheel key
If the hydro lock and recoil starter assembly is not your problem, you next need to check the flywheel to see if there is any damage or if the flywheel key is also damaged.
You must remove the starter recoil assembly (as we did in the previous section) and the fan disc and starter cup.
With the recoil starter assembly removed, you can see the fan tray and the starter cup behind it. The flywheel is located behind them.
Beyond that is the flywheel, where the flywheel connects to the center shaft; you’ll find the flywheel key. Check for any cracks or other damage that could cause the flywheel to hang or not spin properly.
Piston stuck
Now that we’ve ruled out the top 3 easiest causes, we’ll inspect your piston to see if it’s stuck.
This could be due to the generator running with no oil or more oil and the pistons not being lubricated and not moving (at all or easily) within the cylinders. If your oil is very low, fill accordingly, you can also drip a tablespoon of oil into the combustion chamber through the spark plug hole and let it sit for some time. After about an hour, try pulling the recoil cord slightly with the spark plug still removed to see if the added lube allows the piston to release itself.
If the piston is stroked inside the cylinder, the piston is at the bottom. Check for any gouges or rust on the cylinder walls.
It could be that the piston has been running without oil for too long, and the excess heat is causing the piston to bind to the cylinder. This is known as a catastrophic engine failure. If that’s the case, you’re not going to get things running, and you’re probably looking for a new generator instead of spending money on fixing things like this.
Your piston may also rust due to a lack of oil or water from the exhaust pipe, sitting on top of the piston and seeping down.
Damaged camshaft compression release
Finally, if none of the above causes is your problem, the compression release device on the camshaft inside the crankcase may need to be fixed.
To do this, you have to disassemble the entire generator, which may or may not be to your liking. We enjoy fixing generators and other small engines as a hobby, but this is one we’d probably turn over to a mechanic and pay to have done.
When you try to start a generator with a recoil cord manually, the camshaft release allows your valve to open slightly. It doesn’t allow for a perfect seal during the compression phase of the piston’s travel, which makes pulling the cord very difficult.
Once the generator starts and starts working on its own, the momentum of the engine working on its own at 3,600 RPM will immediately release the compression release, and from then on, you will have a perfect seal in the compression phase.
So, although this little part inside the crankcase is rarely damaged, it will take a long time to start the generator until it can be repaired.
Conclusion
The best practice to avoid generator rope stiffness is regular maintenance and vigilance. Ensure the generator is stored and running on a dry, level surface, enough oil is inside, the exhaust is not leaking, and the carburetor is working correctly. This should prevent most of the above failures.
Generator Hard to Pull Start FAQ
Should the choke be open or closed when starting the generator?
When starting the generator, the choke should be closed. Closing the choke restricts the air supply to the carburetor, allowing the engine to draw in a richer fuel mixture and start more efficiently. The choke can be opened when the engine revs up and reaches some speed and consistency.
This allows more air to enter the engine and mix with the fuel, creating a leaner mixture and making the engine run smoother and more efficiently.
Why does my alternator crank but not start?
If your generator cranks but won’t start, there is a fuel supply problem. Please start with the primary fuel filter, making sure it’s clean. Next, check for air in the fuel supply. You can do this by opening the bleed fitting on the auxiliary fuel filter or the fuel injection pump.
Why is my generator having trouble starting when it’s cold?
When the temperature drops, especially when the temperature drops below 40°F, the generator will start to have trouble starting. This happens because the engine and its components are too cold to function correctly.
What are the common causes of generator failure?
Generator failure is often due to lack of maintenance, not enough fuel supply, insufficient cooling, improper installation or wiring, dust and debris buildup, alternator failure or poor quality fuel. Regular maintenance, checking fuel supply and ensuring adequate airflow are essential in preventing generator failure. Generators shouldn’t be overloaded and quality fuel should be used to avoid running inefficiently.
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In this guide, BISON takes you through the steps to how to start a generator for the first time and every other time you how to start a generator after that.
