No Spark on my c175 KT17

[Gas Man 19]

I bought this tractor out of a barn it has been sitting in for some 10 or more years.  I have power to the "+" side of the coil (with the key on) and intermittent power on the "-" side of the coil when cranking.  I believe this indicates that the points are working.  I filed the points just to be sure.  I am on my 3rd - $30 ebay coil and I have replaced the condenser.  STILL NO (real) SPARK!!   If I turn off the lights in the shop, I can see a very very tiny spark at the plugs.   I hooked up a small block Chevy coil to one of the spark plugs and i get good spark.  None of the EBAY coils would OHM out from the positive terminal to the spark plug terminal.  Could I have received 3 bad coils from 3 separate sellers?

[Gas Man 19]

I bought this tractor out of a barn it has been sitting in for some 10 or more years.  I have power to the "+" side of the coil (with the key on) and intermittent power on the "-" side of the coil when cranking.  I believe this indicates that the points are working.  I filed the points just to be sure.  I am on my 3rd - $30 ebay coil and I have replaced the condenser.  STILL NO (real) SPARK!!   If I turn off the lights in the shop, I can see a very very tiny spark at the plugs.   I hooked up a small block Chevy coil to one of the spark plugs and i get good spark.  None of the EBAY coils would OHM out from the positive terminal to the spark plug terminal.  Could I have received 3 bad coils from 3 separate sellers?

[gwest_ca-(File Mod) 10,491]

Is the condenser matched to the coil used?

 

Coil check starts on page 32

Garry

[peter lena 8,050]

did you check out your GROUNDING AREAS ? i would also check out all the electrical connections , sounds like electrical transfer is being robbed , with tiny spark response. 3 bad coils would be very strange, pete

[Gas Man 19]

Thanks Pete!  I hear what you are saying, but the points are 6 inches from the coil with no connections????  I changed the condenser last and haven't had anyone to turn off the shop lights for me to see if I can see any spark.  I'm thinking about wiring up 2 Chevy coils I have on the shelf

[ZXT 2,394]

You should be able to see the spark easily in the daylight. Have you tried running power directly to the coil from the battery to bypass the electrical system on the tractor? 

 

Does your original coil produce this weak spark as well?

 

EDIT: You wired up the SBC coil on the tractor through the same spark plug leads? Was this through the tractors electrical system or jumped from the battery? Will it start and run on one cylinder with the SBC coil?

Edited November 13, 2019 by ZXT

[953 nut 51,630]

5 hours ago, Gas Man said:

Could I have received 3 bad coils from 3 separate sellers?

Could be, but not too likely. They all probably came off the same Chinese assembly line. Have you tested them with the condenser unhooked? A bad condenser could kill the spark, was the same condenser used on the bow-tie coil? Lots of people have reported good results wit a Harley  Davidson coil, even heard of people that used a twin coil pack from a GM late model engine.

[Gas Man 19]

I haven't tried to start it with the SBC coil on 1 cylinder, but I'm going to!!  I have a few SBC coils laying around, I'm thinking about using jumper wires and wiring up TWO coils.

[Gas Man 19]

I tried wiring up a Chevy coil to one of the cylinders and the spark was better but not great.

It still wouldn't fire.

Edited November 16, 2019 by Gas Man

[953 nut 51,630]

Have you given a try without the condenser?