Tools Needed To Repair Small Engines

You don't have to own a lot of tools to repair small engines. What you will need will depend on how deep you're going into the motor.

small engine tools

Aside from basic hand tools, you will need a few specialty tools, plus a few testing tools that you may already have.

First, there's the diagnostic tools:

Ignition Testing Tool

There's several ways to test spark on a small engine, but I find this Briggs & Stratton spark tester to be fastest and easiest to use.

test spark on small engine
Small Engine Spark Tester


Compression Tester

On a used single-cylinder engine in decent shape, 60 psi is good compression. For checking engine compression, you'll need an engine compression gauge.

tools needed to work on small engines
Hand-held engine compression tester with quick-release

The two common varieties of compression gauge will have either a rubber tip (that you need to hold down) or a thread-in fitting that goes into the spark plug hole.


Engine Tachometer

The Briggs & Stratton tachometer is an easy way to verify engine RPMs. To use, hold the tach firmly anywhere on the engine, and slowly turn the top until the wire vibrates at the greatest swing. Then remove it and read the rpm on the dial.

tools needed to diagnose small engines

The Briggs tach works on most small engines, including magneto-equipped flatheads, Honda GX series, and Honda clone motors. It will also work on V-Twins such as the Briggs Vanguard and Predator 670cc.


Valve Spring Compressor

A valve spring compressor like this Lisle 23300 works well with many small engines.

Lisle 23300 small engine valve spring compressor
Removing Valves On A Tecumseh Flathead Engine

The tool is designed to handle 3/4" to 1-1/16" valve springs. Two bottom arms are included with the tool; the extra one has a smaller opening for a tighter fit.


Piston Ring Compressor

Fits cylinder bores from 1-1/2 inches to 3 inches. Made in USA by Lisle.

small engine ring compressor Lisle 18500

Shop: Small Engine Ring Compressor


Three-Jaw Puller

The many uses of a three-jaw puller include flywheel removal. Prying off a small engine flywheel with a screwdriver may damage the soft metal and is not recommended.

small engine flywheel remover
Tecumseh Flathead Flywheel Removal


Cylinder Hone

If your cylinder wall has a shiny finish, you'll need to break that glossy glaze and leave a nice cross-hatch pattern. This allows the new piston rings to seat properly.

A 3-stone hone like the one pictured below is also called a glaze breaker.

small engine cylinder hone


Torque Wrench (Inch-Pounds)

torque wrench in inch-pounds

Shop: 1/4" Torque Wrench (20-200 in/lbs)


Engine Measuring Instruments

An important step in a complete engine rebuild is inspecting and measuring worn parts. Although most of us are more mechanics than machinists, the need sometimes arises to precisely measure clearances, wear, and play.

Feeler Gauge

A feeler gauge, or gap gauge, is used primarily for checking ignition point gaps and valve tolerances. They are made up of thin metal blades, and each blade is a different width of precise thickness. These are marked in either thousandths of an inch, or millimeters.

tools needed to work on small engines

The blades usually range from .0015" to .035" (.038 to .889mm).

Long feeler gauges may be needed for valve adjustments on some engines.


Dial Bore Gauge

To accurately measure the inside diameter of a cylinder, a bore gauge is needed. The bore gauge I have is a ToolUSA TM-34260. It covers two to six inch bores, has a bore depth of six inches, and the dial has .001" increments.

small engine dial bore gauge

Shop: Dial Bore Gauge

Just as important as good measuring equipment is the ability to use these tools correctly. These include measuring devices such as a micrometer, dial indicator, dial bore gauge, and a feeler gauge.


Digital Caliper

Essential to precise engine building is a quality caliper. Dial calipers are less expensive than digital calipers, but digital ones have an LCD display for easy reading.

digital micrometer for small engine build

Remember that micrometers, dial indicators, and dial bore gauges are precision measurements, and need to be treated as such. For consistent and reliable results, keep them clean and out of harm's way.


Spark Plug Gapping Tool

Spark plug gap gauges come in several styles. They all achieve the same results. Pictured below is a 'ramp-style' spark plug gauge.

spark plug gap gauge


Hand Tools

If your American-made engine was manufactured prior to 1980, non-metric tools will probably suffice. Chances are you already have some basic hand tools. These should include:

Box End/Open End Wrenches from 1/4" to 1" (Shop)

Combination Wrenches 7/16" to 1" (Shop)

Combination Wrenches in Metric (Shop)

Screwdriver Set (Shop)

Hammers (Shop)

tools needed for small engine repair

Ratchets in sizes 1/4", 3/8", and 1/2" (Shop)

Breaker bar in 1/2" (Shop)

Six-point sockets from 7/16" to 7/8" and 12mm to 19mm (Shop)

Deep-well Sockets (Shop)

Socket Extensions in three drive sizes from 1-1/2" to 12" (Shop)


Inexpensive Tool Kit

If you're just starting out, Dewalt makes a good mechanics tool kit for the money. It's a 142-piece set that has three different sizes of ratchets and plenty of wrenches. Also included is a driver set. Built into the case is a neat little storage box for any extra bits and pieces you may end up with.

tools needed to work on small engines

Shop: Dewalt Mechanics Tool and Socket Set


Most small engines were designed to be fixed by their owners, but when you get to major repairs, there are several tools that may be a bit out of reach for the average DIYer.

Valve Face Cutting Tool

On a small engine, the valve widths are usually smaller than an inch. Neway offers valve seat cutters individually as well as in master mechanic kits.

small engine valve seats

I contacted the Neway company directly and they were kind enough to advise me on what I needed. They make valve cutting tools for every engine size out there!

Neway valve seat cutter kit

Shop: Neway Valve Seat Cutters


Related Articles:

Best Hand Tools
Digital Caliper Review
Ratchet Buyers Guide