The spark plugs on my rebuilt 223 six have sooted up for the second time. This is my '59 F350 dump truck. I drive low speeds, short distances. Lately not long enough for engine to warm up. I also maybe screwed up and dumped some old fuel in tank. I want to eliminate possibility of weak spark and replace what looks like original coil. Any recommendations on what coil? Wires? I have to order new plugs and don't want to replace them again without coil. Thinking higher temperature range plugs too.

 

Ignition coils are very often unnecessarily replaced. They most definitely fail, just not very often. Ford literature specifies the correct ohms resistance for the primary and secondary coil windings. Testing should be done when at normal operating temperature. Coils get hot. Check spark color & quality at coil wire terminal and at plugs. It is difficult to find serviceable ignition condensers for contact points today, it is important for best possible spark.

It is generally a mistake to install a higher than factory heat range spark plug when the problem is fouling. It's barking up the wrong tree. This is because the factory heat range plugs were on the hot side to begin with.

Tuning the carburetor for the correct AFR throughout the operating range is what you're looking at if the ignition is straight. Pig rich fuel delivery is most likely the problem.

Idle mixture defects will quickly load plugs up. Defective power valves or power circuits will also foul plugs, along with incorrect jetting. Also high float levels. Spark plugs will burn very clean with modern gasoline and good sharp tune, hardly any "color" will be evident after a highway run.

 

Thanks, I'll check ohms and spark color.

 

A quick way to tell if it has a weak spark orange or red it is weak. Should be blue. Best check is the voltmeter.

 

I would also say it is likely too much fuel.

 

Have yellow spark. VOM apparently two hours away at daughter's house. Crappy meters I have here not much help but had an old coil in garage that read a little higher (10,000 vs. 8,000) but yellow spark using a new plug. I didn't find ohm reading for coil in my Ford manual but did find my plug gap was too wide .035". Manual says .028-.032". Regapped and engine started but would only run with choke closed and popped and complained when revved up. I disconnected fuel line and pumped out some gas. I had dumped four gallons of old gas into tank a while back. Added five gallons new gas and a little Stabil.

 

Cobarde destello no bueno! Bad connections or grounds possibly. Or, if the engine has been rebuilt - repainted - ? The distributor itself needs a good ground to block. Try grounding the distributor housing to the battery ground terminal with jumper cables.

A defective ignition condenser can cause trouble too. If you have a couple old school Autolite or Standard, Blue Streak etc kicking around in your junk box you could try those. Thing is, condensers eventually can go bad just sitting on the shelf. Avoid like the plague those el-cheapo no name ignition condensers sold everywhere from you-know-where.

 

Not working it hard or just puddling around with an engine with foul the plugs. I use my old John Deere MT very sparingly in the in the summer months and it spits and sputters at times. In the winter, I drag out the next years wood, scrap with back blade and haul for loads of wood to the cellar. The thing starts (with a crank), and runs great. I had an old timer tell me that would be the case years ago but have since found it to be true for myself. You carb settings could indeed be a contributor but old iron does like to work!

 

Gracias amigo. The neighbor I texted to borrow a meter from wasn't home but said from symptoms he thinks condenser too. He is going to test it for me mañana.

 

After you find out what your problem is you might try a Pertronix conversion. You can use your original dizzy. It will also help the plugs burn good, and hopefully will be trouble free. As stated before quality ignition parts now days are hard to locate.

 

Thanks. I'll look into it.

 

John It may be a good idea to dump the gas completely and start fresh with non-ethanol until all other items are sorted.

Pertronix is the best bang for the buck in my opinion! Red didn’t like to start on cold damp mornings before but NEVER hard starts since I did the Pertronix Flamethrower (stay with the original version)

 

This is California. We only have crap gas. Most diesel here is biodiesel too.

 

Dont they sell Non ethanol for boats and lawn mowers?? Here you have to look around and find a station or two that carry non-ethanol and it costs almost $1 per gallon more

 

You can buy small containers at Home Depot but I don't know of any stations.