Intruders-Alert

Here's an easy to make tester to load up the coil to check for a strong spark. Would like to give credit for this but can't remember where i found it.

As you can see from the pic it's a 3" nail on one end with a few grooves filed or ground in the end to fit the plug cap. The other, just some thread bar with a point on. the gap is 7mm. Earth to engine some where. Turn engine with both plugs out and check spark. If its not consistent or not there you have a weak coil. Or something deeper in the mix It's down and dirty but quick.

Great idea, but I wouldn't use wood. The moisture in wood can cause it to carbon-track, bypassing the gap. Get a block of nylon or similar plastic at a hardware store, or even use a plastic box that has walls rigid enough to hold the points.

WintrSol wrote:Great idea, but I wouldn't use wood. The moisture in wood can cause it to carbon-track, bypassing the gap. Get a block of nylon or similar plastic at a hardware store, or even use a plastic box that has walls rigid enough to hold the points.

Good plan ^ only used wood cos that was all i had at the time

In college, we used a neon sign transformer, about 20kV, and welding rod to make a Jacob's ladder. We drilled holes in a board to hold the rods, and it eventually failed. You could see the lightening-shaped tracks forming around the rods, then it started to smell.

This sure fire method is free:

Back when I was about 13, a friend and mine were building a go cart, we had an old Homelite chainsaw engine and couldn't get it to start. We didn't know if there was any spark. Didn't have a spark plug wrench, I told my 5 year old brother to hold on to the plug wire to keep it out of the way. He said no, it would shock him, so I handed him a pair of pliers and told him to hold it with them. Gave a hearty pull on the starter rope, the pliers went about 20 feet in the air, he screamed and ran for the house yelling for mom. When she came out to see what had happened, and I told her what we had done, she had trouble keeping from laughing, but no problem with grounding me to he house for a week...

Better grounded to the house than the magneto.

navigator wrote:Better grounded to the house than the magneto.

By the end of the week she was so sick of me...

http://shop.advanceautoparts.com/wcssto ... i_larg.jpg

These are fairly cheap, have an adjustable gap, and work well. For those who dont have the tools or desire to build your own. That said, I love the DIY approach to things. It's great when you see a problem and find a way to solve it using what you have.

I like these because they allow you to see the spark with the engine running. Also if the plug is dead, they won't spark. If the plug is shorting out, like they do with a cracked insulator, it will still show a spark.

Used to have one that I bought through JC Whitney, years ago (I won't say how many), but loaned it to someone and never got it back.

https://www.walmart.com/ip/Lisle-Inline ... 3=&veh=sem