missing and low power

[Ken Arms]

I finally got my 34 back together enough to be a yard driver, the 59ab was running perfect but very suddenly developed a skip and and low power. I'm running a Bubba built crab dist, Conn Ken rebuilt carb and pump. gas tank is new Bob Drake and gas line is new. I,m running on 12v with new coil with built in resistor. Feels like a fuel issue. After what seemed like for ever to get fuel up to the carb bowl it started and ran flawless for about two or three laps around the pasture and then started this problem. It seems OK when first started but once the engine is warm it begins. Also will sputter at idle but mostly under load. Any thoughts? Ken

[drolston]

Sounds like the coil breaking down as it gets hot. When cold, pull the coil wire out of the distributor and crank it to see what kind of spark jump you get. Should jump 1/2 inch to ground with blue to white spark. Then run it until it is hot and starts to stumble and try that test again. Weak yellow spark on both tests suggests condenser and points are going bad. Weak only on the test while hot says bad coil.

[slowforty]

Also check the contacts on the Ignition switch. My 40 acts the same way, Barely touch the switch and the motor stops running.

[50fordcoupeman]

Different engine set up but had same symptoms.........turned out to be the coil.

[B_man_Al]

Don't forget the condensor ... I had this exact problem a few years ago . It turned out to be the condensor failing at high temperature. I bet a lot of good coils have been trashed when the real problem was a bad condensor!

[Mart]

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Fuel cap not vented?
Rotor arm tracking through to shaft?*
Crab cap tracking through to retaining clip?*

Do you have any parts you can substitute? Coil for example? Condensor? Preferably parts from another running vehicle.

*I have experienced both of these.

[edhd58]

Don't underestimate the possibility of trash in the new fuel lines that may have made it to the carb jets.

[Seth Swoboda]

90% of fuel problems are ignition.

[DD931]

The last time this happened to me it was the condenser.

[edhd58]

[QUOTE=Seth Swoboda;1526284]90% of fuel problems are ignition.[/QUOTE

Not trying to be a smart ass, but fuel problems are fuel problems. Ignition problems are Ignition problems. Or do you mean 90% pic the time when you think it's a fuel problem it turns out to be Ignition.

[scicala]

Originally Posted by edhd58

Don't underestimate the possibility of trash in the new fuel lines that may have made it to the carb jets.

If it was dirt in the carburetor, it would be very odd that dirt would only contaminate when the engine was hot. Dirt in the carb isn't usually an intermittent problem. It's there to stay.

Sal

[Seth Swoboda]

[QUOTE=edhd58;1526692]

Originally Posted by Seth Swoboda

90% of fuel problems are ignition.[/QUOTE

Not trying to be a smart ass, but fuel problems are fuel problems. Ignition problems are Ignition problems. Or do you mean 90% pic the time when you think it's a fuel problem it turns out to be Ignition.

You got it.

I find that we most often blame a poor running engine on fuel first when it in fact was an ignition related problem. Statistically the odds are better that it is ignition. How many components are there in the flathead fuel system? A tank, line, pump and carburetor. How many components are in the ignition system? On/off switch, coil, resistor, spark plug wires, distributor that includes points, condenser, ignition timing set properly, rotor, cap and all the wires in between. There are just more components involved in the ignition system so therefore if not everything is up to 100%, you have a problem. Both fuel and ignition systems are simple. But with fuel, you either have fuel delivery or you don't. That's real simple.

[Seth Swoboda]

My advice is to check voltage to the coil first and also inspect the resistor. The next step is to pull the distributor and check the point gap and if something looks suspicious then have your distributor timing set on a machine by one of the guys on this forum that have a distributor testing machine and can set timing by dwell.

[Ken Arms]

Thanks everyone, so far I have tried another coil and condenser but still no luck. wile I had dist out I cleaned the points a bit with sand paper. I think I should start it, wait for the failure, then pull a plug and look for a blueish spark. Maybe that would help to eliminate ignition? Ken

[Seth Swoboda]

Originally Posted by Ken Arms

Thanks everyone, so far I have tried another coil and condenser but still no luck. wile I had dist out I cleaned the points a bit with sand paper. I think I should start it, wait for the failure, then pull a plug and look for a blueish spark. Maybe that would help to eliminate ignition? Ken

While you had the distributor out did you measure point gap with a feeler gauge? That would tell you some information about how your distributor is acting. Have you ever had the timing set on a machine? You said Bubba rebuilt the distributor but how long ago? Your points may have moved since then. I'm almost certain your problem lies in the distributor.

Also, did you measure the voltage going to the coil? How about the primary and secondary resistance across the coil? When you put your volt meter to these issues it helps by knowing these values for trouble shooting.

[Ken Arms]

UPDATE....I finally fixed the issue. It was a fuel starve problem. Why I never bothered to simply look down the carb horn wile it was running poor (DA) I don't know, it was obvious one side had a spray and not the other. With help from Charley NY I found a tiny piece of dirt that had plugged one emulsifier tube. Thank you all . Ken

[BUBBAS IGNITION]

Originally Posted by Seth Swoboda

90% of fuel problems are ignition.

Seth,

You got to quit this , 90% of all ignition problems are FUEL????

[BUBBAS IGNITION]

Seth ,

[Seth Swoboda]

Originally Posted by Ken Arms

UPDATE....I finally fixed the issue. It was a fuel starve problem. Why I never bothered to simply look down the carb horn wile it was running poor (DA) I don't know, it was obvious one side had a spray and not the other. With help from Charley NY I found a tiny piece of dirt that had plugged one emulsifier tube. Thank you all . Ken

It would have been running on 4 cylinders only then, correct?

I had a similar problem once but it only ran on 4 cylinders all the time and at idle. I pulled plug wires one at a time to determine what barrel was not providing fuel.