How to check for spark

[prolineez]

My 115 Yamaha 2 stroke runs bad over 4000 rpm. How do I check to see if all cylinders are firing at high rpm. I don't want to spend a lot money on a timing light or anything else. I'm thinking of hooking something up to each ignition wire with a light or something that's visible so I can see if each plug is firing. Is there such a tool?
Thanks

 

[Big Keepers]

Re: How to check for spark

Start that puppy up, stand in a bucket of water and touch the wires with your fingers. If it hurts a lot, you've got spark.

What does "it runs bad over 4,000 RPM" mean? Is it rough? Is it not getting up on plane? There are a lot of parameters there but if you have good spark at idle, chances are it is good at wide open throttle. You'll probably have a different problem causing it to "run bad."

Invest in a spark checker. CDI makes a nice one, you can check all six cylinders at once. It has four brass colored posts on each side so you can check as many as 8 cylinders at once. You probably have what four cylnders? So you unplug all the wires from the plugs, put them on this spark checker and crank the motor about six times or so. If you can get the spark to jump a 1/4" gap or slightly more, then you're fine. Check someplace else. It might be timing, it might be a bad pulser coil, it may even be fuel and not ignition.

 

[Ray Neudecker]

Re: How to check for spark

Many times more likely to be a fuel restriction problem than fire. Failure to repair will likely lead to a broken powerhead.