Have an ignition problem. Motor cranks, and I appear to have some fuel burning in the cylinders, but it won't fire up. When I stop cranking it stops. The good news is I have strong blue spark on all 4cylinders. Fuel is getting to plugs. But when I crank it, I will see a little exhaust smoke rising out of water, but it doesn't fire up- I don't even hear the familiar pop pop pop and normal RPM surge of ignition, so I'm thinking the fuel is being burned or partially burned, but with the pistons are in the wrong position when the spark occurs. If I hadn't noticed the exhaust smoke on the water, I'd never even have thought I had fuel burning in the cylinders- I don't have the familiar pops you hear when fuel ignites in the cylinder. I believe this has been an intermittent problem in the past, but now the motor won't fire up. I just get a little exhaust smoke as long as I keep cranking the motor.
Often after I stop cranking, the flywheel will kick backward nearly a full revolution, and when it doesn't kick backwards immediately when I stop cranking, if I leave the switch in the ON position- if I so much as touch the flywheel, jiggle the throttle, or even flick the choke solenoid a couple times, the motor will suddenly fire for one second- and the flywheel will go backwards about one revolution. Maybe this is normal, since the 1972 uses a battery style CDI and I figure anytime the sensor coil sends a pulse there will be a spark to a cylinder. But normally I would think one would have to turn the flywheel atleast a quarter turn to get a firing. If I so much as sneeze on the flywheel it will kick backwards once after I stop cranking.
Before I pull the flywheel to check for a sheered key, or a problem with the sensor coil, or timer base or anti-reverse spring etc... I was wondering if having the sensor coil connections reversed at the pulse pak could cause this symptom. The replacement pulse pak I got (which provides strong blue spark on all 4 cylinders) had very short leads to work with and I couldn't match the familiar color coding to the wires coming from the sensor coil, so I might have those two connections reversed. Would that mess up the timing of the ignition and cause this symptom? Or should I go get the flywheel puller and plan on a thorough inspection of my distributor, sensor and all the connections under the flywheel. I have the service manual, but I'm hoping to avoid pulling the flywheel if I can avoid it.
Also this pulse pak had an extra green wire coming out of it. I'm familiar with the blue, purple, the black grounds, and the two wires that connect to the sensor coil under the flywheel, but I don't know if the green wire needs to be connected. I don't see a connection for a green wire in the service manual. This appears to be an after market replacement pulse pak.
One last symptom. The old pulse pak would often cause a loud buzzing sound to be heard under the flywheel if I left the key in the on position after cranking. The new pulse pak doesn't do that. but I'm wondering if this is just another intermittent problem one gets if they have a loose or leaking sensor coil or problem with thier anti-reverse spring.
Often after I stop cranking, the flywheel will kick backward nearly a full revolution, and when it doesn't kick backwards immediately when I stop cranking, if I leave the switch in the ON position- if I so much as touch the flywheel, jiggle the throttle, or even flick the choke solenoid a couple times, the motor will suddenly fire for one second- and the flywheel will go backwards about one revolution. Maybe this is normal, since the 1972 uses a battery style CDI and I figure anytime the sensor coil sends a pulse there will be a spark to a cylinder. But normally I would think one would have to turn the flywheel atleast a quarter turn to get a firing. If I so much as sneeze on the flywheel it will kick backwards once after I stop cranking.
Before I pull the flywheel to check for a sheered key, or a problem with the sensor coil, or timer base or anti-reverse spring etc... I was wondering if having the sensor coil connections reversed at the pulse pak could cause this symptom. The replacement pulse pak I got (which provides strong blue spark on all 4 cylinders) had very short leads to work with and I couldn't match the familiar color coding to the wires coming from the sensor coil, so I might have those two connections reversed. Would that mess up the timing of the ignition and cause this symptom? Or should I go get the flywheel puller and plan on a thorough inspection of my distributor, sensor and all the connections under the flywheel. I have the service manual, but I'm hoping to avoid pulling the flywheel if I can avoid it.
Also this pulse pak had an extra green wire coming out of it. I'm familiar with the blue, purple, the black grounds, and the two wires that connect to the sensor coil under the flywheel, but I don't know if the green wire needs to be connected. I don't see a connection for a green wire in the service manual. This appears to be an after market replacement pulse pak.
One last symptom. The old pulse pak would often cause a loud buzzing sound to be heard under the flywheel if I left the key in the on position after cranking. The new pulse pak doesn't do that. but I'm wondering if this is just another intermittent problem one gets if they have a loose or leaking sensor coil or problem with thier anti-reverse spring.