Smoke is bad

[Snerdguy]

I got my GY6B engine completely reassembled with a new carb. Turned it over and it idled beautifully for 2 minutes. (I have witnesses) Then, a wisp of smoke cam from the area of the fly wheel and it quit with no more spark. I didn't cry, frustrated as I was. So, I am trying to understand why the ignition would fail like that. I probably have to replace the coil. But, I wondered what would cause that to fail and should I replace the CDI to be sure?

I took some resistance measurements on the generator. Mine has 5 wires. It is unplugged.

Blue/White to Blue/Red = 603 ohms
Blue/White to Green = 158 ohms
Blue/White to yellow = open
White to Yellow = 0 ohms
White to Green = open
Yellow to Green = open
Blue/Red to Green = 440 ohms

Does anyone know if these are correct?

[bear]

What all did you do to your engine? is your stator and pulse pickup ok? I ask because the exact same thing happened to me when I put a new cam chain, piston, & rings in my gy6, and I'm still trying to find the problem! I've put new stator, pickup, coil, & cdi, and still searching!

[Snerdguy]

I was going to put a larger cylinder on the engine. Ordered it from a company that said it fit ALL GY6 engines. Took the old one off only to discover it didn't fit because mine is the B engine with the two bolt valve cover and the seller of the jug kit had apparently never heard of it. So, I had to inspect and completely reassembly the old cylinder which seem to be in good shape and reinstall it and reset the timing chain and check the valves. I also installed a new carburetor. Like I said, it ran for two minutes.

I have been doing electrical diagnostics on the generator based on information I am finding on the net. I know that the trigger coil has a peak no load voltage of 9. 6 VP and the power coil puts out 56.2 VP no load. I am going to put the CDI back and check the voltages again. I found a circuit diagram for the CDI and I think it's just a triggered voltage doubler. I would like to find some technical specifications for the CDI because it may be affected by the timing of the trigger pulse. That's where I stand at the moment.

[Snerdguy]

I may have found an anomaly. I was testing my ignition coil with an ohmmeter to determine if it was bad. I found infinite resistance from the spark plug connector to the primary terminals. I thought that seemed wrong. So I unscrewed the spark plug cable a and checked the components. I found that the spark plug connector tests open and the rest of the coil and wire are all conductive. That does not seem normal. I would appreciate some guidance. Shouldn't that be conductive? They are on other engines. Does anyone know about the spark plug connectors going bad?

[bear]

Sorry buddy I'm just about totally ignorant on most of the electrical part of these things, I just keep replacing till it cures whatever it is!

[Snerdguy]

I am pleased to announce that my Kart engine RUNS! It was the spark plug connector. There was no visible indication that it was bad. Only checking it with the ohmmeter told me it was open.

So, it is better to buy a ten dollar Volt-Ohm Meter from Harbor Freight then to curse the dead engine.

[Masteryota]

Be careful with those HF meters. I picked one up with the free coupon, and was planning to use for just home stuff(110v-220v) and quickly realized just how sub par they really are. Checking continuity would likely be ok, as it is more go/no-go, but the resistance readings were way off, compared to my Fluke 117, which stays at the shop.

[bear]

I agree "Yota" I think my HF meter is a t-rd!! very inaccurate and can't really get it to pinpoint on a reading!

[Snerdguy]

I have half a dozen of those free Harbor Freight meters. No doubt about it, they are not very accurate and not good for repairing electronics. I also have a better meter for that purpose. But, they are quite handy for determining the presence of voltage or whether a part is conductive or open. You can use them to find a short or check a battery voltage, to trace wiring, test coils, check diodes, test fuses and countless other things.

The meter can also tell you if a breaker is bad or if an outlet or wire is hot. Just by learning the basics of how to use it (read the instructions or look on the Internet), you can save hundreds of dollars in repairs and, possibly, medical bills. Another reason I specifically like the freebie meter is that if I lose it, crush it, drop it, get it filthy or burn it up, I just throw it away and get another out of my tool chest. I also keep one in the vehicle tool box in a zip lock bag just in case.

If you have a kid that likes your tools, give them a Harbor Freight freebie meter and some parts and batteries to test. It will keep them busy and encourage them to learn a valuable skill.

[bear]

Yep, you pretty much nailed it on the head there!!!

[Masteryota]

Originally Posted by Snerdguy

I have half a dozen of those free Harbor Freight meters. No doubt about it, they are not very accurate and not good for repairing electronics. I also have a better meter for that purpose. But, they are quite handy for determining the presence of voltage or whether a part is conductive or open. You can use them to find a short or check a battery voltage, to trace wiring, test coils, check diodes, test fuses and countless other things.

The meter can also tell you if a breaker is bad or if an outlet or wire is hot. Just by learning the basics of how to use it (read the instructions or look on the Internet), you can save hundreds of dollars in repairs and, possibly, medical bills. Another reason I specifically like the freebie meter is that if I lose it, crush it, drop it, get it filthy or burn it up, I just throw it away and get another out of my tool chest. I also keep one in the vehicle tool box in a zip lock bag just in case.

If you have a kid that likes your tools, give them a Harbor Freight freebie meter and some parts and batteries to test. It will keep them busy and encourage them to learn a valuable skill.

Thats basically all I use mine for, live outlets, and continuity checks. The voltage readings on mine were about 20% off.

[bear]

Yea, inaccurate as h-ll! lol