Sooty, black plugs ???????
 

Have a 36 LB engine that's easy to start first thing{warm weather}, drive it awhile, 10 miles or so, its harder to start. I have tried several plug variants, ngk ab-6, autolite 386, gap 0.25, it fouls them all. Have a newly rebuilt, max 97, charlie tested, fuel pump, and a skip haney coil/set distributor. Engine runs well, drive it 45 to 55 mph tops. It runs around 190 all the time. I use no corn gas, and yes its fresh, any thoughts here? Thank you:D

Re: Sooty, black plugs ???????
 

Corn gas will make it leaner

Re: Sooty, black plugs ???????
 

I haven't tried that, thanks for reply

Re: Sooty, black plugs ???????
 

Corn gas will give you grief. DONT use it. Fit a vacuum gauge to your intake manifold and compare the gauge readings with a chart. What size jets are in the carb? Check that the float level is correct. Make sure air filter is not restricted. Regards, Kevin.

Re: Sooty, black plugs ???????
 

Surely it's just running over rich for some reason? Starts easily. That's because it's over rich. Like having the choke on.

I've never ran a 97. What are the common causes of over richness on a 97? Float? needle valve? That's where I'd be looking.

Mart.

Re: Sooty, black plugs ???????
 

you have a leak in the internals of the carb. remove carb, fill with gas thru the vent tube and let stand on a cloth or paper towel and see if the gas is going thru while it is sitting. next change to a smaller jet. I have tried the speedway adjustable jets for multi-carb set ups and they have worked out great. either way you are getting way too much gas and as Mart says check the settings on the carb

Re: Sooty, black plugs ???????
 

Check to make sure your air filter in not restricting. Some of the small air cleaners do not flow enough air. You could check by removing filter and see if it helps.

John

Re: Sooty, black plugs ???????
 

I agree with John in Illinois. Clean the plugs, take the air cleaner off and see if it runs better. I had to ditch a pair of air cleaners on my avatar roadster that looked cool but were operating like a choke.
While the air cleaner is off, visually verify that the choke is coming all the way off.

Re: Sooty, black plugs ???????
 

Good ideas from everyone....John's thought is often overlooked, been there myself.
An internal leak on Stromberg is usually the mechanically operated power valve.

Whether new or used these babies can leak. The leak occurs when the motor is running and producing vacuum drawing fuel from the acc pump well out thru the J tubes when not needed. Uncle Max is THEE guy however and let's get the real scoop from him.
Charlie ny

Re: Sooty, black plugs ???????
 

I have a original, 34 air cleaner on this carb, the kind with the copper screen, you wash with solvent, then oil. I do not have the horse hair top piece in the air cleaner. thanks to all for the reply's.

Re: Sooty, black plugs ???????
 

I agree with John as well. There was a slew of Chinese import air filters that Speedway and several of the other speedshops including the one I used to work for were having issues with. they were produced with an inferior filter element and wouldn't allow air to flow resulting in a bunch of fouled plugs, mine included.

Re: Sooty, black plugs ???????
 

I talked to Max last week about my sooty, black plugs, he suggested that I try a carb riser, said it could help, with hard starting. I have looked around, and there are several versions, anyone have one on their early engine? What thickness?

Thank you

Re: Sooty, black plugs ???????
 

I run a K&N in my stock '40 air cleaner. Fits like a champ. Sure beats that original fuzz they used.

Re: Sooty, black plugs ???????
 

Philips, do you have a K&N number for the filter?

Frank