Spark Plug Brand - Help

[earlybaymitch]

Thank you so much Glenn!

[lowN2slo]

So, seems i have now fouled the new Bosch plugs. FML. Running rich still. Car idles really nice, after a few minutes a slight misfire develops. Hard to notice during idle, but definitely it there under load (on the gas).

Dizzy cap good, no burn marks or archcing
Rotor good
Seems to idle nice, had the timing adjusted last year and should still be set the same as I haven't touched anything. Can the timing just be off on its own?

Carb is stock 30 pict 1 air mixture screw adjusted till the car stumbles then 2.5 turns back to even out.

Appreciate any input. Plug wires? Condenser would be bad on start up I think? Seems ok on start up.

Sean

[mukluk]

Your mixture screw isn't set correctly. It isn't "in until stumble then 2.5 turns out", it should be tuned as follows:

Two and half turns out from fully in is simply the common starting point for the mixture adjustment.

What size idle jet do you have installed?
What is your fuel pressure?
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1960 Ragtop w/Semaphores "Inga"

[lowN2slo]

I will re-set the air/mixture screw and see. 127.5 main jet. Unsure of fuel pressure, how do I check that?

[mukluk]

To test your fuel pressure you'll need to temporarily install a fuel pressure gauge, one suitable for carburetted engines, teed inline between the pump and the carb. For a single screw carb you'll want to see 2-3psi -- excessive fuel pressure will lead to an overly rich mixture.

What size is your idle jet, the one screwed into the right side of the carburetor?
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1960 Ragtop w/Semaphores "Inga"

[lowN2slo]

55 Idle jet - Haven't checked the car yet. Been raining all day, hopefully can do something tomorrow. Appreciate the replies.

[lowN2slo]

Pulled plugs again, cleaned up. Car idles beautiful, I checked air/mixture screw and adjusted as stated above. Still have slight misfire under load. Definitely and improvement though. Not fouling plugs as before.

[mukluk]

Good to hear the fouling issue is fixed.

For the misfire under load, are you certain it's a misfire or is it possibly pinging? Pinging will sound sharp, somewhat akin to shaking a metal can with some marbles in it, and typically can't be felt whereas a misfire tends to sound more dull and will often be felt as the car jerks slightly.
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1960 Ragtop w/Semaphores "Inga"

[lowN2slo]

Yeah it was definitely a mis-fire. Only on acceleration though. Couldn't figure it out so I had a new Empi 30 pict 1 carb on the shelf. Long story short, I swapped it out and it's running great.. for now. I know the Empi carbs have some issues, time will tell.


Thanks everyone!

[VWFIXER]

I always default to oem of the period. Kinda mental about it.
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( ) Cheap
( ) Fast
( ) Reliable

Choose 2

Over a million air cooled miles driven and 15,000+ cars serviced.

[Helfen]

Got all the parts for my tune up on my 64 1200. The BOSCH plugs are made in Russia!

[VWFIXER]