CDI and Top Dead Center question

Posts: 1684

I had a customer ask me the below question about his 150cc kart.
I didn't know what to tell him.

Help me understand this electrical system.......A 4 cycle engine should fire the plug every two revolutions. How can the above system detect Top Dead Center on the firing stroke?

Posts: 1093

I believe the GY6 is a "wasted spark" engine. The spark plug fires on both the compression stroke and the exhaust stroke.

Jamie

Posts: 1893

Spool is correct.

Posts: 1215

that was a good question, i have pulled the plug out before and turn motor over and its looks as the plug fires constantly.
i think spool has answered the question in my mind.
pud

Posts: 1229

When you take the plug out and fire the ignition against a grounded bolt or the frame it appears the spark is continous.

Glade

Posts: 248

Posts: 1832

Posts: 201

Spool is correct.When you look at the flywheel you have a pad tacked to it,every time that pad passes under the ign. trigger the plug will fire and this accures just before the piston reaches tdc on both intake and exhaust stroke. This is common with single cylinder engines. TOM

Posts: 594

Ok so if you crank the engine over and get No spark...what would cause that,besides the obvious. CDI,COIL,STARTER RELAY,ETC. We replaced them all and cannot get spark to the plug.
Let me start from the beginning. Monkeyjockey washed his buggy after our last ride. It started and ran fine.He put it away,then went to get out yesterday,and viola nothing. He brought it over to my house,pulled the plug and sure enough no spark.Put a new plug in it checked the spark and had very little,but it did spark. put it in the buggy and nothing. pulled the plug back out and no spark. Hook up a test light and a volt meter,and went to changing parts and testing wires. Got no power to CDI,coil,only the red wire going to or from regulator has power.yellow&pink wire from stator are dim and have low voltage(under 5 volts) this is while cranking over the engine. All the connections were checked & blown out.Starter relay was blown out(with air).Disconnected kill switch. All it does is turn over. Am I missing something?
The only part we did not replace was the stator,we did change the pickup coil(I had 1 left over from my old stator. Everything else we blew out with air. I'm sure it's something so obvious but I sure can't find it. If any one else has any ideas I would surely be interested.

Mike

Posts: 248

Could there be a problem with some of the wires themselves? Did you replace the spark plug cable to the coil? Battery fully charged?

Just throwing out ideas here. Hope one of them works! Smile

-Mike