1970 124 Spider Spark Plug/Ignition issues

[SquareGrouper]

Completely redid fuel and brakes. Car ran great. Sat for a few weeks then started and seemed like running on 3 cyl. Pulled #3 plug wire while running and it made little to no difference. Swapped that plug with #1 then dame issue with #1. So first guess is the plugs. Where can I find the correct plug for this car. New to the electrical on this vehicle but figured plugs are easy place to start before getting into dist cap and ignition coil. Plugs that came out are Magnet Merell which I never heard of. THANKS!

[bradartigue]

What you're describing isn't a problem with your plugs at all. If you are fouling a plug it typically isn't the plug's fault, something is awry in that cylinder - bad head gasket, bad valve seal, something like that. The fact that you swapped the plug to #1 and it still wasn't firing - did you bother to clean the plug?

Magneti Marelli made the entire electrical system for your car; if you have Marelli plugs then are most likely the correct ones.



Marelli part number is F8LC
NGK Part is BP6ES

[azruss]

if the problem moves with the plug, then the plug is the issue. Everybody makes a plug for these cars. I always had best luck with champions on early spiders. As I remember N6Y or N9Y if you want to burn a hotter plug.

[bradartigue]

if the problem moves with the plug, then the plug is the issue. Everybody makes a plug for these cars. I always had best luck with champions on early spiders. As I remember N6Y or N9Y if you want to burn a hotter plug.

I'm assuming they just moved a good but fouled plug to another cylinder. I should have been clear.

[SquareGrouper]

if the problem moves with the plug, then the plug is the issue. Everybody makes a plug for these cars. I always had best luck with champions on early spiders. As I remember N6Y or N9Y if you want to burn a hotter plug.

Yes, this.^^^^

All plugs looked the same. Didn't try cleaning them. Since I have no idea how old the plugs are, I am going to just get new ones today. Found an NGK cross reference for this car. Car will only run with the choke on, and when I remove the plug wire on cyl #3 there is very little change in the attitude on the engine vs removing the plug wire from other cylinders. Now, when I swap that plug with the #1 cyl plug, the problems transfers to the different cylinder. I'm probbaly confusing the hell out of everyone with my overanalyzation!

[bradartigue]

You have two different problems:

- If the choke needs to be on for the engine to run then the mixture/jets/something is out of tune in the carburetor.
- If the problem with the plugs is as you describe then yes, replace them

If the new plugs cure the ignition woes than get your mixture correct. If your carb is running super lean and requiring the choke to run then you may be burning up plugs (like your #3) or fouling them to being unusable (so when you move them they continue to fail).

Test the ignition before you mess with the mixture. It may also be that you simply have the timing so poorly adjusted that it isn't firing at the right time, resulting in the need for a nasty rich mixture (choke ON) and fouls plugs like mad.

[majicwrench]

Timing is not going to have anything to do with it, you couldn't have it so far out it would affect the mixture that much. Fix your problem.

But like said above, swap plugs see if all cylinders run. Are your currect plugs balck and wet on the business end??

Then yes, car obviously should run without choke on. These carbs often plug the idle/low speed jet resulting in an issue like yours.