Fixing My John Deere 100 Series Not Starting Woes

John Deere 100 Series won’t start? You’re not alone. Most times, it’s a dead battery, a bad safety switch, or old gas. I’ve had the same problem with my E130 after winter.

I spent hours finding the cause. So if you’re tired of guessing, I’ll show you how to fix it—step by step. No guessing. No wasted money. Let’s get your mower running again.

Start Here: Two Types of No-Start Problems

Before you do anything, ask this:
What happens when you turn the key?
Does the engine crank—or stay silent?

That one question makes a big difference. I found this out the hard way. My John Deere 100 Series sat all winter. When I tried to start it, nothing. Let’s break down the two types of no-start issues.

No-Crank: Nothing Happens When You Turn the Key

What it feels like:
You turn the key… and get nothing. No click. No crank. Maybe the lights work. Maybe they don’t.

Common signs:

• Total silence
• One loud click, then nothing
• Lights come on, but the engine doesn’t move
• A faint hum or buzz

Most likely causes:

• Dead battery or loose cables
• Blown fuse
• Faulty safety switch (seat, brake, or PTO)
• Bad solenoid or starter

If the engine doesn’t crank, it’s an electrical issue. Don’t worry about gas or spark yet. The engine needs to turn first.

Cranks But Won’t Start: Engine Turns But Won’t Run

What it sounds like: You hear “ruh-ruh-ruh,” but it won’t fire. No bang. No go.

What it means: You have power, but the engine lacks fuel, spark, or compression.

Safety First: Prep Before You Start

Take 3 minutes to get ready. This helps avoid shocks, sparks, and wasted time.

Power Down and Unhook the Battery

• Park on a flat surface
• Pull the key
• Remove the negative (black) battery cable first

This cuts power and keeps things safe.

Pick a Safe Spot

You don’t need a workshop. A flat driveway, garage, or dry backyard works fine.
Avoid wet ground or hills.

Quick Tool Checklist

Here’s what I keep in a small mower box:

• Digital multimeter (for voltage and switch tests)
• Spark tester (see the spark, don’t guess)
• Socket set and pliers
• Starting fluid + carb cleaner
• Business card (great for coil gaps)
• Fresh fuel (non-ethanol is best)

Fixing a No-Crank Issue in Your John Deere 100 Series

If your mower won’t crank at all, don’t rush to buy parts. Start simple. I’ve chased bad leads for hours—only to find a loose wire or blown fuse. Here’s how to find the real issue.

Check the Battery (Voltage & Cables)

Start with the battery. Even if it looks okay, it may not have enough power—or the cables might be loose.

How to test it:

• Grab a digital multimeter.
• Set it to DC volts.
• Touch red to the (+) and black to the (–) terminal.

What the numbers mean:

• 12.4V or more? Good.
• Under 12.0V? Charge it.
• Under 11.5V? Battery might be dead.

Check the Fuse and Main Power

A blown fuse can stop your mower cold—with no sound at all.

Steps to check:

• Find the fuse—usually under the seat or near the battery.
• Pull it out and look at the wire inside.
• If it’s broken or burnt, swap it with the same amp size.

Test the Safety Switches

Your mower won’t crank unless a few things are “just right”:

• Brake pedal fully pressed
• PTO switch turned off
• You’re sitting on the seat (on some models)

These work through small switches. If one goes bad or gets wet, it can break the whole system.

How to test:

• Unplug each switch.
• Use a multimeter in continuity mode.
• Press or hold the switch. No “beep”? It’s bad.

Check the Solenoid and Starter

If you hear a click when you turn the key—but the engine stays dead—this is the spot to check.

What the click tells you:

• The key switch works.
• Power gets to the solenoid.
• But the solenoid or starter may be bad.

Try a bypass test (if you’re careful):

• Use a screwdriver to jump the two big posts on the solenoid.
• If the starter spins, your solenoid is bad.
• If nothing happens, the starter or battery is the problem.

Use gloves and be safe—this test sparks real power.

Diagnosing a Crank-But-No-Start Problem

If your John Deere 100 Series cranks but won’t start, that’s a big clue.
Power is getting to the starter, but the engine isn’t getting fuel, spark, or compression. Here’s how I break it down.

Use Starting Fluid First

This is always my first test. It’s fast, safe, and helps you focus on the right system.

Steps:

• Remove the air filter.
• Spray a quick shot of starting fluid into the intake.
• Crank the engine right away.

What the results mean:

• If it fires (even for a second), spark is good. You’ve got a fuel issue.
• If nothing happens, spark or compression is likely the issue.

Why it helps: I once tore apart a carb for hours—only to find I had no spark. Now, I always start with fluid.

If It Fires: Check the Fuel System

If the engine fires, your ignition system works. Now focus on fuel delivery.

Fuel Age and Ethanol

Gas older than 30 days (with ethanol) can go bad.

Ethanol pulls in water and leaves sticky gunk—especially in winter blends.

Fuel Filter and Lines

A clogged line or filter can stop fuel flow.

• Check for pinches in the line.
• Replace the filter if it looks dirty or brown.

Fuel Pump or Solenoid

Turn the key and listen near the carb.
Hear a click? That’s your fuel solenoid working.

No sound? It could be bad.

If your model uses a vacuum fuel pump, check the lines for cracks or rot.

Carburetor Blockages

If the bowl has fuel but none reaches the engine, the jets or float valve may be gummed up.

I’ve fixed dozens by pulling the bowl and spraying carb cleaner through the jets.

If It Doesn’t Fire: Check for Spark

If starting fluid does nothing—not even a pop—your engine likely has no spark.

Use a Spark Tester

• Pull the spark plug wire.
• Connect a tester in-line (costs about $10).
• Crank the engine and look for a blue spark.

No spark? Move on.

Kill Wire Test

• Disconnect the kill wire from the ignition coil.
• Try cranking again.

If you now have spark, something else (like the key switch or safety switch) is grounding the coil.

Sheared Flywheel Key

If you do have spark, but the engine fires at the wrong time, check the flywheel key.

This small part can shear when the blade hits something hard.

Advanced Checks: Compression & Mechanical Issues

If you’ve got fuel and spark, but your mower still won’t start, it’s time to look deeper. These checks are less common—but they can stop your John Deere 100 Series cold.

Thumb Test for Compression

Here’s a fast way to test compression—no tools needed:

• Remove the spark plug.
• Put your thumb over the hole.
• Crank the engine.

What to feel:

• Strong pressure? You’ve got compression.
• Weak or no push? You’ve got a problem.

Compression Gauge Test (More Accurate)

Want real numbers? Grab a compression tester. They cost under $30 at most U.S. auto stores.

Steps:

• Thread the tester into the plug hole.
• Crank the engine a few times.
• Read the PSI.

What to look for:

• Over 80 PSI? You’re good.
• Under 60 PSI? You’ve got a real issue.

Bent Pushrods in Briggs Engines

If your mower cranks slow, backfires, or sputters, it might have a bent pushrod. This happens more often than you’d think—especially after the engine overheats or hits something hard.

Signs to watch for:

• Loud puffing sounds from the carb
• Cranking but no compression
• Uneven valve motion

How to check:

• Remove the valve cover (just a few bolts).
• Turn the engine by hand.
• Watch the rocker arms.

If one moves less than the other—it’s likely a bent pushrod.

When to Call a Pro

Sometimes, it’s smarter to stop guessing. If you’ve:

• Checked fuel, spark, and compression
• Tested fuses and safety switches
• Still can’t find the fault—

Call a local small engine tech.

These problems need a pro:

• Valve damage
• Timing gear failure
• Hidden wire damage deep in the harness

My Real-World Maintenance Routine to Prevent No-Start Issues

Most no-start issues don’t just happen—they build up over time. Bad gas, weak batteries, and dirty carbs all sneak in. I’ve learned this the hard way. So now, I follow a simple routine that keeps my John Deere 100 Series running strong—season after season.

These tips work great in U.S. areas with long winters and wet springs—where small engines take a beating.

Battery Care (Especially in Winter)

If your mower sits for months, the battery drains—even when it’s off.

What I do:

• Remove the battery at the end of each season.
• Store it in a dry spot (like a shelf in the basement).
• Hook it to a trickle charger once a month.

Use Fuel Stabilizer Every Fall

Ethanol gas breaks down fast. In just 30 days, it starts gumming up your carb. Winter blends make it worse—especially in states like Minnesota or New York.

My routine:

• At the end of the season, add Sta-Bil or Sea Foam to a full tank.
• Run the mower for 5 minutes to move it through the carb.

Bonus: It also helps stop moisture from building up in the lines.

Lesson learned: I skipped stabilizer once. The next spring, I had to clean out three clogged jets. Never again.

Clean the Deck and Carb After Wet Seasons

Spring mowing leaves wet grass packed around the mower. That buildup leads to rust, poor airflow, and carb problems.

What I do every June:

• Scrape the deck with a plastic putty knife.
• Blow out the engine bay with a leaf blower.
• Spray carb cleaner into the air intake (engine off).

Check Safety Switches Every Spring

A bad safety switch can stop your mower cold—without any warning.

My spring checklist:

• Unplug each switch.
• Use a multimeter in continuity mode.
• Press the switch and listen for a beep.

I keep a small log and test each one before the first mow of the season.

Read More: Craftsman LT1000 Will Not Start?

Conclusion: You Can Fix This—Step by Step

If your John Deere 100 Series won’t start, don’t worry. And don’t go buy new parts right away. Start simple. Ask: what happens when you turn the key? Then follow the signs.

Most of the time, it’s one of a few things. A dead battery. Bad gas. A loose wire. Or a safety switch that’s not working right. I’ve seen them all—more than once. And every time, taking it slow saved me time and money.

I know it’s annoying to hear just a click—or nothing at all. But trust me. You can fix this. You don’t need to be a mechanic. Just stay calm, use your tools, and check one thing at a time.

FAQs: John Deere 100 Series Not Starting