I’m always suspicious when a job goes smoothly; I prefer a mower to put up a bit of a struggle. But when it goes smoothly, it’s usually because you’ve got the right tool for the right job. This page is dedicated to those tools.
Fueling System Tools
A fueling system fault, hands down, is the most common fault a lawnmower will have. The reasons are simple, carburetors are small and block up with crap easily; check out this post “Lawn mower starts then dies.”
The second reason, people (including me) forget to use a fuel stabilizer in the gas tank over the winter (It keeps the gas fresh). Check out this post, “How to winterize your mower.”
Cleaning the fueling system, in most cases, fixes the problem. Check this post out, “Carburetor cleaning,” but sometimes you’ll need to bite the bullet and fit a new carburetor. Check out the “Carburetor cleaning video” here.
Anyway, here’s a list of the tools you’ll find really helpful if you troubleshoot your fueling system and many other small engine problems.
Some of the pictures on this page link to Amazon.com, where you can check the price and delivery of products. We participate in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Stabil Fuel Stabilizer
Mix this with the gas when winterizing your small engine. Gas isn’t what it used to be; it goes stale, in some cases, after just one month. Bad gas causes gumming, and that’s a carburetor killer. A stabilizer will save you money and stress in the long run. Picture links to Amazon.com. Check out “Adding stabilizer video” here.
When cleaning your carburetor, you’ll need this stuff. Gumming is a sticky substance that’s hard to shift. The carb cleaner will remove it; however, if your carb is really bad, save yourself some work; go ahead and buy a new carburetor. Picture links to Amazon.com. Check out the “Carburetor cleaning video” here.
Lucas Oil Treatment
Lucas is an oil treatment designed to help reduce oil consumption by revitalizing engine seals. As the engine ages, the rubber sealing materials tend to get hard, allowing oil to slip past and into the combustion chamber, where it’s burnt off. The result is, as you know, a ton of exhaust smoke, high oil consumption, reduced power, misfiring, etc.
Lucas won’t fix a worn-out or damaged seal; it’s not a bottle of magic. Picture links to Amazon.com.
Oil Extractor / Syphon
You’ll find this tool really useful if you need to drain the gas tank, and you will if the gas is stale. The siphon will remove it without fuss or mess, and it can be used for extracting the oil too. Picture links to Amazon.com.
Fuel Line Clamp
Some small engines will have a gas tap, which is really handy when removing the carburetor and stops gas from flowing all over the shop. However, most engines won’t have one; these useful clamps simply squeeze the fuel line and prevent a spill while you perform surgery. Picture links to Amazon.com.
You’ll find these nylon brushes super useful when it comes time to clean those tiny passageways of the carburetor and jet. Use these in conjunction with the WD Carb cleaner. Picture links to Amazon.com.
Ignition System Tools
The ignition system of all small engines gives plenty of trouble; after the fueling system, it’s the next most likely area to fail. Checking for spark is often the very first test we do. Check out this video, “How to check spark.”
Common problems include:
- Plug dirty
- Plug gap off
- Armature/Coil failure
- Broken flywheel key
The kind of tools we’ll need when working on an ignition system range from spark testing to measuring tools. I’ll list the most common tools together with what they do and a link to Amazon.
This tool is used to check both the spark plug and the coil for spark. Sure, you can check the spark without the tool, but it’s not as good; the tool is designed to stress the whole ignition system. Picture links to Amazon.com.
Spark Plug Gapper
This tool isn’t strictly necessary if you have a feeler gauge, but it’s a lot easier to handle. If you haven’t guessed, you use this tool to check the gap in your spark plug. It is a simple, effective tool. Picture links to Amazon.com. Check out the spark plug gapping video here.
Fly Wheel Puller
Now, this tool is a must-have if you’re removing the flywheel. Why would you want to remove the flywheel? Sometimes the flywheel key shears; it stops your engine from starting. The key is really cheap, and it’s easy to fix when you’ve got this tool. Picture links to Amazon.com.
Every home needs a Dvom (Digital Volt Ohm Meter). It’s used to check for continuity in lawn mower wiring and voltage when there’s a battery fitted. But don’t use this tool to check the spark; that will kill it. I use mine every day. I have the previous model to this, and it’s still doing its job. Picture links to Amazon.com.
I like the Cartman boosters; they stay flexible even in low temperatures. They have double grip clamps, and the set is guaranteed for five years. Picture links to Amazon.com.
This is a clever battery charger, plug it in, attach it to your battery, and forget it. After it finishes charging, it trickle charges, and it’s safe to leave it on all winter. Picture links to Amazon.com. Picture links to Amazon.com.
The NOCO jump starter pack is a serious tool, don’t let its size fool you. This little guy fights way above its weight. Capable of starting a diesel truck engine and yet small enough to fit in your glove box. Picture links to Amazon.com.
If you’re reading this section, you might have a more serious problem. But it doesn’t mean you can’t fix it. Small engines are really simple; they need three things:
- Gas/air mix
This tool will test compression, which in turn will help you identify common issues like head gasket failure, sticking valves, or worn/broken piston rings.
Modern lawn mower engines use a compression release valve which helps them start. The trouble is, that a compression release valve will, on some engines, cause an incorrect compression test reading.
While a compression test kit is still useful, a leak-down tester is a more useful tool; it offers readings but also helps actively identify the problem.
Check out “Compression test video” on this page.
It allows you accurately measure pressure loss in the cylinder (you’ll need access to compressed air). But more importantly, it allows you to listen for the tell-tale leaking of air.
- Air from the dipstick indicates a broken or worn rings.
- Air leaking from exhaust/muffler suggests a exhaust valve issue.
- Air leaking from carburetor suggests an intake valve fault.
- Air from the cylinder head suggests a head gasket fault.
This is a compression tester; it’s fitted in the plug hole using the adaptor. Cranked over, the engine produces a compression reading which is read on the dial. The compression readings are matched against the manufacturer’s specs. A low reading can be caused by a simple fault such as a sticking valve. Picture links to Amazon.com. Check out the compression test here.
The OTc is a quality kit and will last many years of use. A leak-down tester will require compressed air. The tester measures how much air escapes a cylinder and helps you find weak rings, valves, head gaskets, etc. Picture links to Amazon.com.
The ABN 26-blade feeler gauge set is marked in SAE and metric. You’ll need this set to adjust the valve lash and is useful when setting the armature/coil air gap. You can also use it to gap spark plugs. Picture links to Amazon.com.
- About the Author
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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.