sparks around spark plugs...

robw

robw

Senior Member
Ok, so last weekend I sprayed some engine degreaser on the engine and cleaned off all the gunk... when I started it up to move it back into the garage... the problems began...

suddenly the engine was running lean... rough running, and it would backfire if I revved the engine. If I covered most of the carb with my hand, it would smooth out and allow me to open the throttle some.

This lead me to believe there was a blockage in the carb, so I pulled it apart, and verified all the jets were open and flowing.

Put it back on... same problems... took it off again and double checked all the jets... put it back on, then double checked the float level... all good.

ran it again... same problems. I took a can of spray carb cleaner and sprayed around all the connections in the intake manifold... to see if there were any leaks... didn't find any at first... but then after a while I found one on the left side underneath, where the intake manifold goes into the head. So I put a little more torque on the manifold bolts... no luck.

I pull the manifold off and it is obvious that the gasket is leaking... end of work... order new gaskets from Snyder's..

new ones came this week. Put them on today. Took a little bit, but eventually got rid of the vacuum leak... hey, I can even adjust the carburetor with the idle mixture needle now...

but... alas... it still isn't running right.. so I go through Les Andrew's step by step trouble shooting... for the 10th time... everything is checking out... I'd previously bought guts for the distributor (original style)... so I put all of them in there and go through Les' trouble shooting again... to include a new cap and rotor.

still no luck... but as it is running this time.. I turned off the lights. Once my eyes adjusted... I could see sparks around the spark plugs... a pretty blue ring around the base of the insulator... right where it goes into the steel part of the plug. It becomes more obvious as I speed the engine up.

I also noticed a bit of sparking from the high tension coil wire to the armored ignition cable... high up, near the junction box. Hmmm... that is a new coil wire too..

so here is my question... these blue rings of sparks around the base of my plugs... does that mean they are probably bad and need to be replaced? Perhaps there are cracks inside the insulator?

Plugs are gapped at about .035.

would bad insulators on the plugs cause the sparks to jump from the coil wire to ground?

hmmm

what do you guys think?

rob
 
ford3 said:
spray the hell out of every thing with wd 40, as bill said blow every thing off
Click to expand...

well, it's been sitting for well over 2 weeks... I'd think it'd be dried out by now... I'll try it, but don't have much faith in that solution...
 
You said this weekend in the first post, now you say it's been sitting for two weeks ????
Point is you have contaminated the wire and plugs, if cleaning them doesn't work, the you'll have to replace. I have an electronic ignition as well, and it has a higher intensity spark. I had the same problem with 2 of my 3X plugs, about 10,000 miles, and ended up replacing all four. Plus the higher voltage does eat away at the electrodes.
 
You can use WD 40 or go to the parts store and get some Wire Drier. It is a silicone spray that will seal the insulators. You have some high resistance somewhere, probably in the plugs. You could try a set of modern style Champions W16Y.

You can also try loosening the plugs and retightening them to get a good ground. On the head and at the nut that holds the insulator.
 
Yup, seems your Engine Cleaner left a conductive residue on your plugs. The current is simply finding the easiest path to ground. Pull your plugs an clean them with a solvent. I use Brake Clean. You might as well gap them while you have them out. But clean the seats good as well. If someone painted the head with the plugs out or the have grime under them, your ground is compromise. Good lesson here, when you have a change in the way the engine runs, ALWAYS blame it on the last thing done to it and eliminate that possibility first. Then go back to the next thing you did. Getting into the Carb if you had not been there recently put you on a wrong road.

I sold a bike once to a guy who adjusted the Cam Timing Chain. Afterwards it was slapping the nylon adjuster. Rather than stopping to think about what has changed, he kept digging and tore the top end down, couldn't put it back together, and blamed me for selling him a piece of crap. Last I knew the bike was rotting in a shed.
 
Agree whole heartedly withQGolden.

And the reason partially covering the air intake allowed you to give some more throttle is because a rich mixture fires with less voltage...
 
Yep, what the boys said about the ignition system.
As far as the air leak. Did the new gasket stop that leak ? Was the manifold checked with a straight edge ? If the leak isn't fixed, and, you can fit about a .010" feeler strip between a straight edge then the manifolds should be fixed.
 
I'd remove the coil wire and spray some WD-40 in the cap and coil towers, then blow dry them. Also spray the coil wire, distributor body, and spark plugs with WD-40 and wipe them dry, then see how it works. Sometimes, once a carbon track is made, it's hard to fix without replacing the part.

BTW, the Model A did NOT come with boots on the ends of the coil wire, and I never use them. I've seen them trap water and cause shorts.
 
New cap, new rotor, new coil wire, no boots.

Cleaned & dried the plugs. Verified the gap on the plugs. ensured plugs had a good ground with the head.

same problem. It may run slightly smoother, but when I go to rev the engine, it bogs down and backfires... if I cover the intake about halfway, the engine will rev without backfiring. Can't tell if the ring of sparks are still there... too much daylight.

double checked the seals around intake manifold... they seem to be working fine. I can spray WD-40 all around them with no change... same for the connection to the carb.

not sure where to go from here... I've done all the troubleshooting the Les' book and it seems to pass all of them.

rob
 
It sounds like a blocked passage in the carb. With all the jets removed, did you use high pressure compressed air to blow out the passages in the carb body?
 
It's pretty obvious (to this electrical engineer) that the ground connection is the problem. The blue sparks around the base of the spark plugs and the sparks up the armoured cable were the giveaways. This is NOT a carburetor issue, guys.
 
You must log in or register to reply here.
Back
Top