Gentlemen,
I completed my first transmission rebuild ( without any extra parts too!) Ya gotta love the old A833. I took the old 84 D150 to inspection to, of course, fail Hydrocarbons. I plan to replace all my vacuum lines, tune up the engine (plugs, rotor, cap), adjust the timing ( 10 off TDC I think), lean the carb mixture til it's just running. My question is that short of doing all this are there any other good hints to help get the truck to pass emissions. I've heard the suggestion of Seafoam being added to the vacuum lines but I don't know if that is effective. I appreciate any input from the experts. Thanks

Chuck Pfeiffer

What is the status and condition of the truck's emission control system? Catalytic converter still in place...and functioning? Air pump, EGR, etc.?
Don't guess, find the spec and set the timing there.
No. Set the idle mixture correctly.
When the truck is configured and tuned correctly, it'll pass. Focus on that goal, not on figuring out how to sneak past the test.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Will do! I forgot to mention the Cat is shot as far as I can see and I will be replacing it. Is Seafoam a good idea? Right now she idles so rough that I can hardly keep it going. All the pollution control stuff is still in place and the Air Motor is spinning ok. Could my crappy Lean Burn computer be causing it to run poorly? Another thing I will try is spraying starter fluid around the manifold and carb to look for leaks.

Well, that right there will cause a failure no matter how well the engine runs. You need a very robust converter to handle the garbage coming off a carbureted engine. Use a Catco #9005, nice and affordable from this outfit.
It's claimed to be a cleaner for the combustion chambers. Me, I prefer BG 44K and/or Chevron Techron for that purpose.
Well, then yeah, it's not going to pass an emission test! Obviously something (at least one thing) is broken or faulty or not adjusted correctly.
Certainly could be. Does this truck have a feedback system (Oxygen sensor screwed into the rear wall of the exhaust manifold's central collector, and a carburetor with a duty cycle solenoid built into the upper carb body)?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I don't have an O2 sensor on the manifold and no solenoid on the upper body. I should probably just get rid of that damn computer and put in an electronic ignition, right?

If your local emission laws will let you do so, by all means you should definitely do that. See the HEI upgrade article.

If you wind up needing a new carburetor; I think I have one remaining on the shelf; send me a PM.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Get her all adjusted correctly, and tuned up.
I addition to the advice above, I've heard that your engine should be fully warmed up before you get to the test station.
A few years ago, someone posted that he would drive his truck to the emissions station in second gear.

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"Ja, Ich fahre ein altes auto."
'78 Volare 225
'67 Charger 318

Oh yeah, replace your truck's lean burn with electronic ignition, or HEI if possible.

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"Ja, Ich fahre ein altes auto."
'78 Volare 225
'67 Charger 318

If the carb has a nitrophyl (plastic) float, replace it. They absorb fuel over time, which raises the fuel level in the bowl, causing the engine to run rich. In the extreme the carb will flood and stall the engine. btdt

Ken

Great advice from all. I will install the HEI. As for the plastic float, I assume you guys know where I can get a proper substitute. The D150 has a Holley 1945. Thanks to all for the help. I've had three dodge cars (63 Dart, 65 Dart and 71 Demon) they all ran so smooth but this is the second D150 ( I exploded a deer with the first one) and they both ran so rough at idle. The first D150 (1982) had a two barrel Carter though. I hope from all the advice I can get this old girl running as smooth as my cars did.

In general, High HC is caused by an misfire ignition misfire, so look at your ignition system first.
BUT, a excessifly lean mixture can also give the same symptoms. A rich carb will generally cause high CO.

Take note, in both cases I said "in general" not written in stone.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Brass float for the 1945/6145 is Walker #100-48.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.