black sooty sparkplugs

[cederholm]

I've had a feeling that my "new " coupe was running rich and now that I find my spark plugs all black and sooty I think my suspicions are true.

What do I do about it? My GAV is totally off but I suspect it's not working correctly. Is there a test procedure for it? And/or should I first set my idle according to the owner's manual?

Thanks,
Carl

[1930artdeco]

Unless you have original jets in your carb it will run rich with todays jets. The closest to original are Renner's Corner jets. They flow test theirs and work better than the regular vendor jets. As for the idle, let the engine tell you how low to go.

Mike

[cederholm]

Thanks Mike, and forgive if this is this is a stupid questions. But are you saying ignore the GAV and swap out the jets, or are the GAV and jet control one in the same?

Originally Posted by 1930artdeco

Unless you have original jets in your carb it will run rich with todays jets. The closest to original are Renner's Corner jets. They flow test theirs and work better than the regular vendor jets. As for the idle, let the engine tell you how low to go.

Mike

[burner31]

If your GAV is not affecting your engine you have a blockage in your carb, need to clean all the ports and passages.

[1931 flamingo]

What plugs are you running??
Paul in CT

[1930artdeco]

Sponsored Links (Register now to hide all advertisements)

If you are using a Zenith, this is how I run mine. Around town I open it up (the GAV) about a 1/4 turn as I have to do a lot of hard stops thanks to the stop lights here. On the freeway I generally close it off or just crack it a bit. I have replaced my jets with ones from Renner's and it runs better. With the old jets I got from the rebuild kit it was very rich even with the GAV closed. Plus, I was running Autolight plugs which are a cold plug. Now I run the 3X plugs and she runs great.

Try, swapping the jets out and then play with the GAV. You may find she runs great the way mines does or you will have to open or close the GAV a little more. Hope this answers your question.

Mike

[cederholm]

Interesting. The plugs are Autolight, though I don't know which ones. What are 3X plugs? I'll look into the jets.

Thanks,
Carl

[cederholm]

I'll look into this - thanks!

Originally Posted by burner31

If your GAV is not affecting your engine you have a blockage in your carb, need to clean all the ports and passages.

[1930artdeco]

The 3x plugs are the expensive ones by Champion. they were originally designed for the Model A so are the correct temperature. The problem is they are now $30 a pop. I think the next closest is the W18(?) from Champion. I got mine from Amazon which runs sales apparently-although I have never seen them on sale.

Mike

[Jacksonlll]

Before you go changing parts, figure out how long it has been since you cleaned your plugs. Model A plugs foul. Simply clean them. A lot of slow driving will cause it to happen more often.

[cederholm]

Hi JacksonIII, I just bought the car, so I don't know the last time the plugs were cleaned but I did just clean them now. I also drive on the streets of Brooklyn NY, lot's of stop and go.

I'll keep an eye on them but I might also check my carb for blockage as noted above, that GAV doesn't seem to be working correctly.

Originally Posted by Jacksonlll

Before you go changing parts, figure out how long it has been since you cleaned your plugs. Model A plugs foul. Simply clean them. A lot of slow driving will cause it to happen more often.

[burner31]

You older guys may remember some of these signs

[cederholm]

Those are awesome!

[Fred K-OR]

Originally Posted by cederholm

Hi JacksonIII, I just bought the car, so I don't know the last time the plugs were cleaned but I did just clean them now. I also drive on the streets of Brooklyn NY, lot's of stop and go.

I'll keep an eye on them but I might also check my carb for blockage as noted above, that GAV doesn't seem to be working correctly.

Did you check to see what type of GAV fitting (if any) you may have down in the bottom of the GAV shaft. I had one carb that I needed this fitting and didn't have it and things did not run well at all. Someone more experienced with carbs may be able to explain to you what I am trying to say. But some cards do require this fitting and some do not.

[FrankWest]

are black sooty spar plugs also a sign of not driving/running your engine enough?

[cederholm]

I know very little about the GAV - I need to investigate.

Originally Posted by Fred K-OR

Did you check to see what type of GAV fitting (if any) you may have down in the bottom of the GAV shaft. I had one carb that I needed this fitting and didn't have it and things did not run well at all. Someone more experienced with carbs may be able to explain to you what I am trying to say. But some cards do require this fitting and some do not.

[cederholm]

Good question, but it would pertain to the previous owner as the car is new to me. Now that the plugs are clean I'll keep an eye on them.

Originally Posted by FrankWest

are black sooty spar plugs also a sign of not driving/running your engine enough?

[Fred K-OR]

Originally Posted by cederholm

I know very little about the GAV - I need to investigate.

I don't know a lot about it either. Just what I found out the hard way.


On one of my carbs, if you take the GAV out along with the thing it screws into, you can look down into the shaft where they came out of. In the bottom, on some carbs there is a fitting that the GAV closes into to close it down or adjust the amount of gas going through. This fitting screws out and you can replace it. On other carbs there is no fitting like this-the GAV just closes against the body of the carb. All this stuff depends on when the carb was made.


Like I mentioned before some people on this site can give you a far better explanation about this subject. And also this may not be your problem but I thought I would mention it just in case.

[WHN]

I would start by changing the spark plugs. “New” plugs will rule out one possible problem.

Gap at 35. I have used the Champion W16Y plug for years. Around town driving, always under 45 mph. Just changed a set that were loading up, car was losing power and running poorly. It’s now running fine.

I set GAV at open 3/4 turn with cold start. Than turn it down to 1/4 or so depending on how I am driving and weather conditions. Enjoy.

[Chuck Sea/Tac]

Originally Posted by FrankWest

are black sooty spar plugs also a sign of not driving/running your engine enough?

It’s a sign of too rich a mixture, idling a lot can certainly contribute.