ok I will admit something else too. I suck at dealing with carborators. I cant tune them to save my life and have never had any luck with them. The only carborator thing I am good at is flooding the engine when I try to start it. right now I have a stock 83' 302 with a two barral that is badly out of tune and I wouldent know if it was in tune if tried.

So can I have your advise everyone on starting the truck (do I pump the gas or not, really I'm that freaking cluless) what do I tune up and how do I know its right.

 

You can actually tune your mixture, idle speed, and ignition timing with a vacuum gauge.

Taken from a post by Lakerat in the Inline Six Performance Forum:

Tuning with a vac gauge
Many racers and engine tuners have opted for state-of-the-art diagnostic equipment but have forgotten one of the simplest, as well as one of the most accurate tuning tools...... the vacuum gauge.
When using any vacuum gauge keep in mind that they are all calibrated at sea level and read-outs in the instructions are in reference to that level. When above sea level all readings will drop one division per each 1,000 feet of altitude above sea level. Thus a reading of 20 inches of vacuum at sea level would drop to 19 inches at 1,000 feet, 18 inches at 2,000 feet, etc. All readings are taken at idle except as noted. If your engine is barely able to sustain 2"Hg vacuum at idle, it will be hard to tune using this method, but it is still useful. In most cases if you use a quality large faced Vacuum gauge, with some experience you can effectively tune your car's fuel and timing systems. Tuning with the engine running compensates for wear in the timing gear and valve train, and therefore providing better results than with the manufacturers recommended settings.

Note: All adjustments are made with the transmission in PARK or NEUTRAL, with the exception of Idle Speed, which is set in DRIVE.
Vacuum Gage ConnectionConnect the gauge to a "manifold" vacuum source, NOT "ported" vacuum, that rises as RPM increases. In most cases this will be a direct manifold source or possibly the PCV port (larger port) on the carb.

Start by first warming the engine and note the idle vacuum reading. Normal vacuum at idle should be 19-21 inches for a six cylinder, or 15-18 inches on a low compression engine. Pre-set the ignition timing so that it is close to the manufactures recommended setting, before making any carb adjustments.

Carb Adjustments To adjust the carb, start by leaning out one of the mixture screws (turn in) until the gauge as well as the engine begins to shudder. Next bring the screw back towards rich (turn out), while watching the gauge.Stop adjusting when the gauge reaches it's highest reading. Then do the same process for the other mixture screw. After each adjustment is made, reset your idle speed.

Small adjustments are best, and in fact "optimum" carb settings on the vacuum gauge (highest reading) is usually richer than it needs to be. In other words, once the highest reading is reached, back-off (or lean) the adjustment approximately 1/4 turn in. You may have to repeat the process a few times to get optimum results, but it's worth the time and effort.

Note: With a properly jetted carburetor, turning either of the mixture screws all the way lean, should kill the engine. If not, you're too rich! This may require re-jetting, or drilling the primary butterflies to add more idle air. Many of the newer "race" carbs allow you to change Idle air bleeds to fix this.

For carbs with 4-corner mixture screws, you have to take a bit more time. You can also run the engine at a "steady-state" RPM of say, 2500 RPM to double-check your secondary mixture screw settings. Do this with temperament! It takes time to get used to what you are seeing as well as if it is actually helping. Each engine will behave differently.

Remember to rev the engine to clear the spark plugs before taking your final reading and readjust if necessary. When you blip the throttle, the needle should drop to as low as 2, pop back up to as high as 26, and quickly level off in the normal zone.


Ignition Timing
After the carb mixture is set, you can proceed with the ignition timing. Slacken the distributor clamp bolt, and with the engine still at idle, advance or retard the ignition until the highest steady vacuum reading is obtained. Then retard the timing until the vacuum gauge reading drops slightly, approximately one half to one inch. In some cases, you may need to retard the timing up to two inches to prevent pre-ignition (pinging).

Note: If you can't get the reading into the "normal" zone by adjusting the distributor then valve timing is the problem. Timing with a vacuum gauge will normally result in timing that is more advanced than what specifications call for, so you need to be alert for any pre-ignition (pinging) in the engine and adjust accordingly (retard the timing if needed).

Your engine should now be tuned to perfection.

 

And yes, when the engine is cold, like first thing in the morning, or after sitting for a few hours, pump the gas pedal a few times before you start it.

 

If your carb is adjusted properly you should be able to pump the gas one time to set the choke and start it. When its cold out, i need to pump mine 3-4 times to give it a little extra fuel. They all seem to have their own little quirks so you need to experiment to see what works for your truck.

 

Watch this video a fellow member made over in the 1973 - 1979 forum demonstrating how a carbureted vehicle should start:

https://www.ford-trucks.com/forums/10...art-video.html

As you can see, a carbureted vehicle can start in any weather and run just as good as any modern fuel injected engine, so long as everything is adjusted correctly. That means a properly set choke is absolutely necessary for cold starts and overall driveability!

Since this is your first carbureted vehicle, you need to understand that it is a bit different than modern EFI vehicles in that now you have a choke and a manual fuel pump to deal with. You will have two starting procedures:

If you drive your vehicle daily, one or two pumps of the gas before starting should be all it takes. As long as the choke is hooked up and set correctly, your truck should start right up, even if the temperature is 0 degrees. It got down to near zero degrees here a month ago, and my own 1985 F150 started right up and continued running without stalling, with only two pumps of gas before starting it. In the summer, one single pump will start the engine every time.

If your vehicle sits for an extended period of time, say, over a week or two, you will need to crank it for about 10 seconds and then pump the gas 7-10 times before you start it, as the fuel bowls in the carburetor will dry up over time.

After your vehicle has been started for the day, you don't need to push the gas down before every start. As long as it is not extremely cold outside, it should start right up. For example, if you stop to get groceries, etc., just get in and turn the key. If it has been say, 5 -6 hours since it was last started, you may need to push the gas pedal down half-way before starting the vehicle.

A 1983 Ford truck would have come with a hot air (thermostatic) choke and an electric assist. The "hot air" is the primary choke and it would have an insulated tube connected from the choke cap to the passenger's side exhaust manifold. This tube typically rusts off, so check to make sure it is still there. If it is not hooked up, your choke will never work as it should. The "electric assist" is secondary and not absolutely necessary but it should have a wire connecting the choke cap to the back of the alternator.

 

Hi Andrew! Even if you have minimal experience and are a little concerned you might make things worse, you can't go wrong with a few blasts of some good quality carb cleaner. Wear safety glasses and read the label! Be careful to not spray the stuff on a hot exhaust manifold! You can also check to make sure that the nuts holding the carb to the intake manifold are tight as well as the screws holding the carb together. I check mine on a regular basis and am surprised how often I find those darn screws have loosened up! Carburetors are old school and they like to be clean and tight to operate at peak efficacy.
Good Luck!
HARFEND

 

Andrew,

Read the info in this thread and watch the video in it, too:

https://www.ford-trucks.com/forums/1...l#post10067564

 

Thats good info! I'm going to pick up a vacuum gauge soon to try this.

 

Thanks for this post! This is a very consice, easy-to-understand explanation of vacuum tuning. I plan to pick up a vacuum gauge as well to tune my engine properly. I hate to ask a dumb question and I know that the answer is somewhere in the posts (can't seem to find it), but on the I6 motor, which way do you rotate the dizzy to retard the timing? (And sorry to butt in/highjack here).

 

I6 engine:
clockwise = retard
counter-clockwise = advance

V8 engine:
clockwise = advance
counter-clockwise = retard

 

Thanks, Lariat, and you're right about chokes. I had a world of trouble starting my ride this winter until I figured out how to use the choke properly. I have a manual choke conversion that my grandpa put in when he owned this rig because he dislikes automatic chokes and just assume convert to manual when they quit working. Anyhow, it seemed like pulling the choke didn't help with starting and it seemed that my high idle was not working. I thought I was pulling it properly but later realized that I needed to push the gas pedal down all the way and pull a little harder to close the choke and click the high idle cam. Now it starts pretty quick no matter what the temp.

 

Choke schmokes. I haven't hooked my choke back up since I rebuilt my engine... It's a PITA to start on cold days, pump, start, die... pump, start, die... pump, start, die... and so on. It still hasn't bugged me enough to finish hooking up the electric choke, then again I'm procrastinator numero uno.

 

I've been meaning to make that my new years resolution... maybe next year.

 

I might have waited except one morning I drained the battery trying to start it, had to limp in the injured car to work in its place--kinda scary when it 2 degrees out and snowstorms coming. The only way I found out was during a tune-up, noticed high idle linkage was in place. Had to play around with the choke and high idle linkage to realize that it was working, I just wasn't working it correctly. Before that, I just assumed that the high idle wasn't working because it had been removed during the manual choke conversion.

 

Thank you everyone, I love this community, I love this forum, and above all I love my truck, and as soon as its out of the shop it IS going to make me some money. Thank you everyone!!