1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Spark plugs constantly fouling on front rotor housing.

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Old 09-24-07, 10:08 PM
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Spark plugs constantly fouling on front rotor housing.

I don't understand why... ever since I got my car, it always foul the plugs or flood the engine. It has been 3 times since I got it in May/June 2006. I can't find the reason why... it has problems starting occassionally but my brother's fb doesn't. I got a new S4 alternator, tried to start it with my bro's battery, I am sure it's fine cause he can start the first time without any problems. My car didn't start at all, I tried many many times... checked the plugs and they were BLACK and 2 of them were wet... I just don't understand why this happens so often. Please help.
Old 09-24-07, 10:11 PM
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Which 2 were wet? Leadings? Check the fuel vent solenoid on the carb. I am having the same problem and i need to fix that somehow. The thing works periodically, and will flood the rest of the time. I think the only reason i can get it to deflood is my ignition.
Old 09-24-07, 10:18 PM
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+1 on the vent solenoid...

You might also want to check the timing and coils, along with proper grounding of the engine. Any of which can lead to a weak ignition, which can lead to the issues you described...
Old 09-24-07, 10:21 PM
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is the carb stock its probly runing lean rebuild or get a new carb
Old 09-24-07, 10:35 PM
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Originally Posted by roterhead
is the carb stock its probly runing lean rebuild or get a new carb
Black is an indication of Rich, not lean. Extreme lean the plugs would be very white.

Rebuilding a carb or replacing seems to be everyones answer to all engine running problems.

Finding the "Real" problem and fixing that,Iis the solution. All else is just guessing.
Old 09-24-07, 10:35 PM
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It's a YAW carb.

I just got new battery cables... rewire them and stuff.

The only 2 plugs that are wet are from the front rotor... near the radiator.
Old 09-24-07, 10:36 PM
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Run a compression test on that housing.
Old 09-24-07, 11:50 PM
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Does your exhaust show black or blue smoke? Black/rich, blue/oil control o-rings.

Check the level of the fuel in the sight windows on both bowls, they should be the same and at the 1/2 way mark. If they are not equal, i.e., the front level is high, then either there is debris that's not allowing the needle to fully seat or the float is set too high,(unlikely if you haven't made any adjustments). Try tapping on the banjo bolt for the feed line to the front rotor. The needle and seat sit directly below it. That may loosen up any debris or sticking of the needle/seat.

If the vent solenoid was bad, both front and rear plugs would be fouling. If spark and fuel level are good, you may have a clogged jet/air bleed.

Since both leading and trailing plugs are fouling on one rotor and not the other, it's not an ignition issue. But make sure the plug wires are fuly seated and not reversed.
Old 09-25-07, 12:11 AM
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I will take a look tomorrow... should I lean it out a bit first?
Old 09-25-07, 12:16 AM
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No, the mix screw adjusts A/F on both sides of the carb. That screw only adjusts idle mix anyway.
Old 09-25-07, 10:30 PM
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Sight level for the float bowls are fine. I had that fixed last month or so. So I cranked the engine without the plugs, and fuel fuse off to pump out the extra fuel in there. It was wet so I didn't put the plugs back in... I will try again tomorrow...
Old 09-25-07, 10:39 PM
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Perform the compression test. Also verify spark to L1 and T1.
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