8n engine dying out

[kenben]

1950 8n side mount dist will only run correctly 10 seconds and acts as if it is
starving for fuel,backfiring untill finally dying out.Have checked/cleaned screen
in tank,screen in bowl and screen in carb.Carb is getting gas.Great gas flow thru
system!Set points a couple times to .025.Still no go.Gotten dark now.Could it be
the sparkies??HELP!!TIA

 

[Bruce (VA)]

Confirm that you have voltage to the coil. Battery voltage, points open. About half that if the points are closed.

Battery voltage means 12.65 volts on a 12v system and 6.35 volts on a 6 volt system. A light will not tell you that. Get a meter. The number 1 cause of no spark or a weak spark is a weak battery.


Do you have battery voltage across the points when they are open? (with the points open, put one probe on one side of the points & the other probe on the opposite side of the points) Verify the gap on the points at .025. Then, dress the points by running a piece of card stock or brown paper bag through them. New points sometimes have an anti-corrosive dielectric coating on them & old points can corrode or pick up grease from a dirty feeler gauge or excessive cam lubricant. (I always spray my feeler gauge blade off w/ contact cleaner.) Make sure you have voltage across the points, as in past the insulator on the side of the distributor. That is a very common failure point on sidemounts, along w/ the attached copper strip. It's hard to find a short there because it is usually an intermittent . So 'wiggle' the insulator & the copper strip a bit when you are doing your checking. If you find the short there, the Master Parts catalog lists everything you need on page 154. You can make the strip and you could also make the insulators as well. But, somethings are just easier & in the long run cheaper to buy. Get the strip, 12209, screw 350032-S, 12233 bushing & 12234 insulator & just replace it all.


If you just replaced the rotor & lost spark, put the old one back in. Insure that the rotor fits firmly on the shaft & that the little clip is there. Make sure the distributor cap is not cracked, doesnt have gouges in it from the rotor or brass shavings & doesn't have carbon tracks. Check continuity on the secondary coil wire. Make sure it is firmly seated in both the cap & the coil. Next, remove the secondary coil wire from the center of the distributor cap, turn the key on & crank the engine while holding the end of the wire 1/4 from a rust & paint free spot on the engine. You should see & hear a nice blue/white spark. If not, you have a bad coil or condenser. Just put the old condenser back in to eliminate that as a possibility.
75 Tips

 

[teddy52food]

condenser.

 

[Tim PloughNman Daley]

Do you have the Sediment Bulb Valve OPEN 2 FULL TURNS? Sometimes it isthe simple stuff. Point Gap is correct for an Angle Mount Dist, plugs too need to be .025. Did you time dist after the tuneup with flywheel marks and timing light? Firing Order correct - 1,2,4,3 CCW? Lastly, 6V or 12V and is wiring correct for that system?

Tim Daley (MI)

 

[Jim L WA]

(quoted from post at 15:21:51 05/09/23) condenser.

Times two, what teddy52food said. It could also be the coil, but they don't typically break down in 10 seconds, more like 10 minutes when they go bad.
The fact that it runs well for that first 10 seconds tells me the spark plugs etc. are fine. If the condenser doesn't fix it and you have checked the items that Bruce suggested, then try bypassing the ignition switch with a jumper wire.
Let us know what you find.
The condenser is part number FD-71 or ECH CS-35 at NAPA. FD-71 is preferable.

This post was edited by Jim L WA on 05/10/2023 at 08:38 am.

 

[kenben]

it was conenser.Thanks all!!

 

[used red MN]

Tim D how could timing or firing order have any affect on it only running 10 seconds? Inquiring minds would like to know. Gas valve could apply. You are a knowledgeable individual on Fords, I am sure you have helped many a Fird guy, clutter helps no one.