Carb ADJ. 2150

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Mar 8, 2004 | 06:20 PM

UncleJesse

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From: Midvale, Idaho

Carb ADJ. 2150

O'k, rebuilding the 2150 Carb on my 1979 F150 Supercab was the easy part. Now I got it on the rebuilt engine and things were good(except mileage) for a while, then it started chugging and sputtering. Originally I set timing by ear. made no adjustments on the Carburator which I got off a 79 Bronco. It was running a little hot about 205- 210uphill, and down to 200 degress coming down hill or idling. when I put the timing light on it it was 21 degrees. so I brought it down to 12 degrees which is what I got from the parts store. Then I saw the specs on BubbaF250's site and adjusted it to 6 degrees. It smoothed out at Idle but when you give it gas it flutters and pops. I rebuilt the Carb and have no instructions hoe to adjust the Idle Mixture Screws. I tried playing with it this morning and thought it was pretty good. when I got on the highway my acceleration was very slow, and at stop lights or taking off it sputters. It hasn't backfired. I've checked all my vacuum lines. I'm not sure were to go from here. I appreciate any help. Thanks. Uncle Jesse

Mar 9, 2004 | 03:28 AM

Ford_Six

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From: The Big, Oregon

When you adjusted the timing, did you disconnect and plug the vacuum advance hose? I had a very similar thing happen with a 79 F-250 with a 400- the vacuum advance is to manifold vacuum, so if you adjust it to specs at idle with the vac line hooked up, you are actually running -13*, and have no vac advance.

Mar 9, 2004 | 09:56 AM

UncleJesse

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From: Midvale, Idaho

I checked the timing with the vacuum advanced plugged, this time. Then adjusted it to 6* BTDC. It was a little rough but smoothed out after I hooked the vacuum advance back up. I played with the Idle screws a little and got it a little smoother. It's better but not right. Took it out for a spin and hd better take off and some of my power was back. most of the sputtering and hesitation is gone. Still have to fine tune it. I did find a leak in the airhorn gasket. on the backside of the carb. Fixing to cut a gasket for it and see if that helps any. thanks Uncle Jesse

Mar 9, 2004 | 02:50 PM

UncleJesse

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From: Midvale, Idaho

something I just read in another forum was about were to hook the vacuum advance up at. It was saying to hook it up from the Carb port. I have mine hooked up to a port in the manifold since there was no vacuum coming from the carb port at idle. Or is no vac at idle how it works? Thanks again, Uncle Jesse

Mar 9, 2004 | 11:12 PM

rainbowATF

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From: Elyria, Ohio

Distributor vacuum

Check the vacuum-emission diagrams for 351M in Mil1ion Gallery in the 1973-1979 Forum. Distributor usually goes to ported carb vacuum; usually port on passenger side of carb in front of choke mechanism. There are other hookups however.

Mar 9, 2004 | 11:36 PM

brown 4x4

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From: Nebraska

Quote:

Originally posted by UncleJesse
something I just read in another forum was about were to hook the vacuum advance up at. It was saying to hook it up from the Carb port. I have mine hooked up to a port in the manifold since there was no vacuum coming from the carb port at idle. Or is no vac at idle how it works? Thanks again, Uncle Jesse

It's supposed to go to the port on the passenger side of the carb toward the front. This is the spark port which will give you no vacuum at idle or WOT, but have vacuum at part throttle. Try it there and reset your timing.

Mar 10, 2004 | 09:39 AM

UncleJesse

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From: Midvale, Idaho

will try this. Its all starting to make sense.

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Mar 11, 2004 | 11:25 AM

bubbaf250

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Turn the idle mixture needles all the way in (just lightly seated, not too tight), then back both sides out 2 turns. That's a good starting point.

Make sure the engine is warmed up, with the choke all the way open when you start the adjustments.

When you change the idle mixture needle position, make sure you turn both sides the same amount (they should always be "in sync").

The objective is to achieve the highest manifold vacuum, with good smooth idle quality, at the correct idle speed (usually about 650-750 rpm), and at the correct static (base) ignition timing.

To do this, you'll need to adjust both the idle mixture needles and the idle speed set screw (and/or throttle positioner device, if you have one) by the throttle lever.

You may also need to re-adjust the distributor to get the timing right. When adjusting base ignition timing, disconnect and plug the hose from the vacuum advance source (carb spark port). Make sure the vacuum advance is connected to the spark port for all other (carb) adjustments.

Getting a good idle tune is usually a repetitive, trial-and-error process, and you may need to make several adjustments to each control to get it right.