Electrical help, car runs then loses spark.

[sofsadon]

I bought my type one without an engine. Installed a crate motor and hooked it up. it runs fine, then after 20 minutes it starts to sputter and run bad, then it dies and wont start. After about a half hour it starts but then starts to sputter and die again. Troubleshooting shows it has no spark, from the coil. I have replaced the coil, condenser, and voltage regulator. Battery is strong. Anyone have any ideas for troubleshooting?

[FJCamper]

Hi Sofsadon,

Make sure you're hooking up the coil right -- terminal 15 is positve -- and where your ignition wire connects. Wiring a coil backwards sometimes allows the engine to run (many variables here), but quickly kills the coil and creates exactly the symptom you describe.

Check to make sure you have a good transaxle ground, and a generator or alternator ground.

Also, touch your ignition switch to see if it's getting hot while the engine runs. You could have a failing switch.

Good luck,

FJC

[sofsadon]

FJC, Thank you I will check.

[Marc]

Your description of the symptom perfectly matches the classic plugged-fuel-tank-outlet-screen; you may want to double-check to confirm the diagnosis.

Let's rule out an ignition problem first.

For the benefit of anyone running points, I give you Kettering troubleshooting 101:
Disconnect the Term 1 wire from the coil, leaving only the power from the ignition switch hooked up to Term 15. Using a jumper wire between Term 1 and ground, see if you don't get a decent spark each time you disconnect it. (If not try another coil).
Next hook the Term 1 wire back up and see if you can get a good spark each time you open the points; also try rotating the engine so that the points are open and then bridge across them with your screwdriver tip. If the screwdriver makes better points than the points do, they need attention. If you get a good spark under these tests but not when the engine's cranking, and the voltage to the coil isn't being dragged down excessively while cranking, then the condenser is suspect.

If there's detritus floating about in the gas tank, the pickup strainer could be getting plugged up as you drive along causing fuel starvation...after the car sits for a while with no fuel demand, the crud falls away from the strainer and things look fine. You may want to remove the gas gauge sender and peer inside with a strong flashlight...

A problem with the fuel tank vent system can cause a similar symptom; if that's suspected, simply leave the gas cap loose to see if it makes any difference.