Lisle In-Line Spark Plug Tester (P/N 20610) Review | SVTP Tool-Tech


Mar 27, 2003
Myrtle Beach, SC
Lisle In-Line Spark Plug Tester (P/N 20610) Review | SVTP Tool-Tech


Anyone who works in industry or passed a 4th grade science class should be familiar with the Fire Triangle. In order to produce fire you need heat, fuel, and a source of oxygen. In a gasoline engine those roles are filled by your ignition spark, atomized gasoline, and intake air respectively. Testing for the presence of air and fuel in your engine is pretty simple, though making sure your spark plugs are firing can be a bit more challenging. Today I’m going to show you two simple ways determine whether or not you’re getting spark.

First, I recently picked up this Lisle Spark Plug Tester (P/N 20610) from Amazon for about $10. It’s a pretty simple in-line device that slips between the spark plug and coil or wire. If your coil is sending current to the plug the little bulb inside the tester will light up. It’s pretty simple. It does have a few limitations though. First, it’s not able to diagnose an issue with the spark plug itself. So if your plug is heavily fouled or damaged it may not fire even if the tester is lighting up. Second, sorry coil on plug guys. This particular tester won’t work for you, but this one (Lisle Spark Tester for Coil on Plug - and method two will.

So if you have a Crank-No-Start issue on a gas motor and want to eliminate the ignition system as a possible issue all you need is a $3 can of ether, more commonly known as starting fluid. Just give the engine a little squirt down the throat-hole and crank her over. If she fires, you know you have spark. We eventually diagnosed this Explorer with having a dead fuel pump.

You do have to be a bit careful with the ether, especially on a diesel. You are introducing an unmetered fuel source into the engine, but I’ve found it super helpful in the field. Another good application is in a situation where you have an engine with a mechanical or vacuum operated fuel pump, and the starter isn’t spinning the engine fast enough to fill the carburetor. A little shot of starting fluid will often get things moving fast enough to fill the bowl. There’s a ton of uses for a can of ether, just keep it away from a certain momma’s boy with a tennis racket unless you want a riot.

If you’re interested in a cheap can of starting fluid or the Lisle Spark Plug Tester you can order either one through the following links. If you do, SVTP gets a sale cut of the sale at no cost to you:

Lisle Spark Plug Tester

Lisle Spark Plug (Coil on Plug) Tester

Cheap Ether Starting Fluid



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