Dies sporadically

[DD in WA]

My 52 12V 8n dies on me for some reason. It'll be running just fine then suddenly die, no sputtering then dying, just dies. If I run it at higher rpms, half throttle or higher it seems to not do this. I've replace the ignition switch, the condenser, and the fuel filter. On the fuel side, I've pulled the hose at the carb and I have a steady stream of fuel. So what should I try next? Thanks.

 

[HCooke]

Next time it dies immediately check for spark. The best way to check for fuel flow is to remove the bolt at the bottom of the carb bowl and check for flow. Your method will not rule out a sticking float or needle valve. But, check for spark first.

 

[soaked]

Agree!

It can take many attempts to find an intermittent issue.

On fuel starvation, bugs or debris (floaters) can block fuel from leaving the tank.

On spark, the primary terminal on the distributor has insulators that can fail intermittently, so primary grounds out, or the copper strip cracks or touches, killing spark.

Trick is to catch in the act.

Will it restart right after it dies?

 

[DD in WA]

Agree!

It can take many attempts to find an intermittent issue.

On fuel starvation, bugs or debris (floaters) can block fuel from leaving the tank.

On spark, the primary terminal on the distributor has insulators that can fail intermittently, so primary grounds out, or the copper strip cracks or touches, killing spark.
View attachment 167680

Trick is to catch in the act.

Will it restart right after it dies?

Yes but I usually have to choke it.

 

[DD in WA]

Next time it dies immediately check for spark. The best way to check for fuel flow is to remove the bolt at the bottom of the carb bowl and check for flow. Your method will not rule out a sticking float or needle valve. But, check for spark first.

Will do. And I'll check the fuel flow like you suggest.

 

[Jim L WA]

This will be an interesting one. The fact that it doesn't seem to do it at higher RPM is puzzling.
When you get it to restart with the choke, then does it quit again right away or not?
What does it have for a battery charging system?

 

[old]

My 52 12V 8n dies on me for some reason. It'll be running just fine then suddenly die, no sputtering then dying, just dies. If I run it at higher rpms, half throttle or higher it seems to not do this. I've replace the ignition switch, the condenser, and the fuel filter. On the fuel side, I've pulled the hose at the carb and I have a steady stream of fuel. So what should I try next? Thanks.

One like that can be hard to figure out sometimes. If it where me I'd hot wire it and run it and if that works and it doesn't die then you have a wiring problem. If it still dies you have a carb problem/fuel problem

 

[ChrisFromCLE]

I would look again carefully at both the coil and condenser. Either can cause this type of stalling failure when hot due to breaking down while under load. Many condensers now days are bad right out of the box.

My ‘52 8N did exactly the same thing - I chased down phantom fuel issues until it was DOA. Changed the points and condenser in the field and it is still running fine five years later….

Whatever it turns out to be, you will find it. Remember, change only one thing at a time.

Good luck,

Chris from CLE