Lisle 20610 Inline Spark Tester, One Size, Factory

Good quality, easy to work with, works great, bright light, like the longer boot for coil packs. Struggled with the shorter one in the beginning. I have the dreaded 5.4l 3 valve v8 F-150 and sparkplugs were just to start with....

Works for its intended purpose

Works great and produces a easily visible light.

Works well but hard to see in daylight especially if you are pull starting. Also, the indication of spark is red/orange. You know you have spark but no way to tell if it's hot and blue. It's better than telling your wife, "Here, hold on to this a second."

There’s an Old Guy in every neighborhood who knows how to fix stuff. Back in the day, our local Old Guy taught me how to check for spark on a small engine by pulling the spark plug, grounding it against the engine block, and having someone yank the starter. You can usually see the plug spark — and about half the time, you get a shock.This tester is way easier, and there are no shocks involved. Stick it between the cable and the plug, turn the flywheel (I use a socket attached to a cordless drill), and the tester either lights up or it doesn’t. Somewhere, that Old Guy is shaking his head.

A great product a very reasonable price!

This is a nice quality item for sure. The boots on each side are good quality rubber and everything snaps together really nice.On my particular tester (see attached photos), I made a few modifications which make this particular tester extra versatile. You can see I have taken a sharp razor blade and cut the boot where it extends on the 90 degree part.I made this modification because I use this tester on both my chainsaws as well as my Toyota pickup and sometimes I need a little access point where i can clip on an external timing light. Sure, they do have induction type timing lights, but those can give inaccurate readings due to spark plug wire shielding and also other spark plug wires nearby. What I have done is cut the boot where it makes a 90 degree turn; this allows me to either use the tester with or without that little section of rubber. When used with the cut off piece installed, then it works like normal. When used without the small length of rubber, then I have a nice clean metal contact point for either a direct electrical clamp or even the induction clamp (away from other spark plug wires). This little upgrade is really nice, just don't grab it with your bare fingers while the motor is running :)You can also see in the photos that I have replaced the light with a length of just plain spring. This allows for a more solid path, which can sometimes help improve idle. Nothing wrong with the original light that is supplied, but when using high voltage coils on race motors, etc. sometimes I just like having a direct path to the spark plug also. It's easy enough to unscrew the plastic housing and return the original light back into the mix also, thanks to the very nice design by Lisle.Great little addition to any tool kit. 5-stars for sure.

Great product