Small Engine Tools
I’m always suspicious when a job goes smoothly, in fact, I prefer a mower to put up a bit of a struggle. But when it does go 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 (Keeps 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.
Anyway here’s a list of the tools you’ll find really helpful if your troubleshooting your fueling system.
Some of the pictures on this page link to Amazon.com where you can check price and delivery of products. We are a participant 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
Fuel line clamp
Ignition system tools
The ignition system of all small engines give 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 post “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.
DVOM
Testing Compression
If you’re reading this section, you might have a more serous problem. But it doesn’t mean you can’t fix it. Small engines are really simple, they need 3 things:
- Gas/air mix
- Spark
- Compression
This tool will test compression, that 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 help them start. Trouble is, a compression release valve will give you incorrect compression test readings.
So if your riding mower or walk behind mower was made in the last 15 years or so, you’ll need the leak-down tester.
It allows you accurately measure pressure loss in the cylinder (you’ll access to compressed air). But more importantly, it allows you 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.
Compression tester
This is a compression tester, it's fitted in the plug hole using the adaptor. The engine is cranked over and a reading of how much compression the cylinder makes is captured on the gauge.
A low reading can be caused by a simple fault such as a sticking valve. Picture links to Amazon.com
John Cunningham is an Automotive Technician and writer on Lawnmowerfixed.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write "How to" articles that help fellow gear-heads with all aspects of mechanical repairs, from lawn mowers to classic cars.