help with carb adjustment

dodge74x4 · Post by **dodge74x4** » Sat Apr 21, 2012 1:33 am

I Took my truck to be smogged today and it FAILED. My CO readings are high. The tech have me a pamphlet to read and it seems as though I may be running rich. Now its been a long while since I've had any real time to dedicate to wrenching on my truck. Can anyone give me a quick rundown of how to properly adjust my carburetor mixture? The truck is a 74' W 100 with a carter 2 barrel mounted ontop of the freshly rebuilt 318. Also what should my idle speed be set at for my set up?

Thanks!
Eric

JimE · Post by **JimE** » Sat Apr 21, 2012 1:10 pm

What transmission? Anyway my book says 750 rpm. As far as your fuel mixture start at 1 1/2 turns out per screw adjust one side til you running smooth then the other side. You never said when the last time the carb was rebuilt, how long the carbs been sitting and so on. Jim

dodge74x4 · Post by **dodge74x4** » Sat Apr 21, 2012 3:55 pm

Torqueflite 727. Carburetor was professionally rebuilt 2 years ago. Almost no miles on it. For the mixture screws, the more turns out the leaner?

JimE · Post by **JimE** » Sat Apr 21, 2012 8:23 pm

"For the mixture screws, the more turns out the leaner?"

It seems to me if memory serves me right you should find a sweet spot between 1 1/2 and 2 turns open. Jim

dodge74x4 · Post by **dodge74x4** » Sat Apr 21, 2012 11:34 pm

Thanks. I'll give that a try

dodge74x4 · Post by **dodge74x4** » Sun Apr 22, 2012 12:14 am

Does your manual have the timing specs as well? If so that would be awesome!

JimE · Post by **JimE** » Sun Apr 22, 2012 11:13 am

Your timing light duty trucks: 2 1/2 Before TDC (D or W100 through D or W200).
Heavy Duty: TDC. Jim

dodge74x4 · Post by **dodge74x4** » Wed Apr 25, 2012 4:43 am

Ok to clarify. I have a 1969 engine (318) with a 727 auto trans.
So...
Timing should be set a 2 1/2 before TDC with distributer disconnected?
Idle speed should be at 750 when warm?
I should find a "sweet spot" between 1.5 & 2 turns out for the mixture screws?

Sorry that I'm being difficult, I'm just anxious to get smog over with.

Eric

JimE · Post by **JimE** » Wed Apr 25, 2012 11:11 am

Correct. Jim

dodge74x4 · Post by **dodge74x4** » Fri Apr 27, 2012 2:06 pm

It appears as though I have 2 idle adjustment screws. Which should I be adjusting?

dodge74x4 · Post by **dodge74x4** » Fri Apr 27, 2012 9:40 pm

I made the recommend adjustments. But I still failed my retest. I'm more than frusterated. I don't know why they even require 40 year old vehicles to test, as there are very few vehicle of that age even in operation. Do u happen to have any other ideas?

It's my understanding that the vapor canister and PCV valve are the only other emissions control devices on my truck. I suppose I could replace them as well. If that doesn't work I guess ill be forking out the money to have it professionally serviced

Sweptline.ORG

help with carb adjustment

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