spark checker

Some time ago there was a discussion about lack of spark or some such thing. The idea of building a spark checker came up. It was a bulb (LED ? neon ? xenon ?) and a length of wire wrapped around a spark plug wire. The induced current in the wire would light the bulb.

Anyone rememeber the details ?

Thanks

Greg

Just hold on to the top of the spark plug tight. The spark only bites when you don't have a tight grip. I was helping get a Navy generator going & it had 1 plug shorted [brand new Champion]. The only way to find it was to hold on to check for spark.

This does not involve slapping yourself in the forehead with the back of your hand...

here is an inductive type, just hold it against the plug wire, it will lite when the plug fires. i have an older one that looks like a pen and has a window in it that glows when the plug fires
spark here

Sure, I mentioned it.
From any source (Radio Shack etc.) purchase an NE-2 bulb. It is a neon glass bulb with two wire leads coming out the base end. They have no mounts, and are easily placed in a rubber grommet to be held in place. An insulated piece of 20 gauge stranded wire is wrapped around a spark plug wire about 15 turns close together, but not overlapping. The end of this wire is connected to one lead of the NE-2. the other lead is grounded to the chassis of the vehicle. This setup will flash with every spark passing through the wire. At idle, the brightness will be pretty high, but it is best seen in dim light, not daylight. As the throttle is opened the brightness goes down because as more air enters the combustion chamber it is easier to jump the spark gap at the plug electrode. As the engine gets to high idle, it will be bright again, due to the vacuum now present. So: there is a way to see load on an engine based on spark voltage (not calibrated, but meaningful.
There are two easy applications, I have built a multi light system and put it at the dash with a bulb for every cylinder arranged in firing order so the array is sequential. Cool at night, and will show a bad plug wire as a very bright light, and a shorted fouled plug as very dim, or out.
Putting it on the coil wire also works, but the repeated flashing does not tell which cylinder is having issues, just that one is.
Running the 20 gauge wire all the way to the platform of the tractor is OK, or it can be made to be seen from standing on the ground. Good luck, the Ne-2 bulbs are dirt cheap, and bell wire will do the job on the wraps. Use black vinyl plastic tape to hold the wraps in place.
A small bent aluminum angle made from 1/8" soft aluminum with enough holes for each cylinder and grommets for the bulbs works well. I am glad you asked!! Jim

I have also got one of those I got it from a friend of the real Champion sparkplug family. It is as you describe, and uses the person's mass as a voltage dump to light. (no shock) I like the NE-2 unit for fun and info on the road/field, and the hand held for shop diagnosis. Jim

jim, now that you mention it, i think mine says champion on it. bought it at napa prolly 25-30 years ago. if i remember it was only a couple dollars. sure beats the heck out of dropping 10 grand for a modus scanner from snap on, and it never needs a software update!!!!

Thanks Jim. The guys over on Brickboard were asking. I'll print it out this time.

Greg

Harbor Freight has them for 4 or 5 bucks. I was there today, should have bought one.

You are welcome, it is an informative and interesting idea. Jim