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Discussion Starter · #1 ·
Failed on Hydrocarbons: 1253 ppm (Illinois Standard=800 ppm)
Passed on Carbon Monoxide: 6.3% (Illinois Standard=8.0%)
Carbon Dioxide Reading: 8.7% (no standard)

I understand that Hydrocarbons are mostly unburnt fuel emissions. I had my mechanic lean out the carbs as best as possible but this did not seem to work. Any ideas on how I can beat this thing?

BTW, it's a stock motor with 100k miles, header, 2.5" exhaust, rebuilt stock carbs, Ramflo air filters and stock ignition. Oh yeah, no emission control devices of any kind.

Thanks in advance for any info,
James.
 

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Discussion Starter · #3 ·
it's a stock ignition system with new NGK plugs, new Nissan ignition components (wires, rotor, points, cap) and bosch ignition coil. it's a little sluggish in the low rpms, but is very spirited from 2500 and on up.
 

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Try checking to make sure the timing is not too far advanced. This will make one fail for sure.

Ken
 

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I agree with Ken. Retart the timing.

I don't know how much, because I'm not sure where its set now. Try the stock specs for starters.
 

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I agree with Ken. Retard the timing.

I don't know how much, because I'm not sure where its set now. Try the stock specs for starters.
 

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my idea:)

I know this might be a stupid idea but no one else said this on the board, but I have seen those things in the auto shop some product forgot the name, but they say you put it in the tank and it will most likely help you pass the emissions, if you want you can try that i think its like less then 10 bucks it might be work who knows
just an idea:)
Zya
yuichi
 

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<b>RE: This worked for me)</b>

I had a K&N Filter on my 78, and was running too rich for the states liking, so I put the stock air cleaner back on and it dropped hydrocarbons by about 100ppm! It might be worth a try for you, because you said you had a ramflo air filter or some such ****.
 

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Another idea:

You could create a vacuum downstream of the carbs to lean out the mixture. I have run engines to get them hot, and then pop a vacuum hose off just before I get to the testing station. It worked.
 

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Discussion Starter · #10 ·
Hey guys, thanks for the suggestions...I think I'm gonna check out my spark first, lean the carbs out even more, and give it a try next week. I'll let you know the results.

-James.
 
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