Carburetor adjustment
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Carburetor adjustment
Ok…. I have a 1979 F150, 300 6 and a single barrel carburetor. The problem I’m having is that when the truck warms up it stalls out, now I have had a buddy of mine that didn’t seem to know as much as he though adjust it, because I don’t know to much about them, I do believe it’s out of adjustment and the automatic choke is not set right. Can anyone give me any tips? Thanks a lot!
John
John
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Joined: Apr 2008
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Tip 1. If the exaust burns your nose its too rich. Loosen the choke cap and turn in the direction of 'lean'. After its warm, if it still burns thy nose, turn the little idle air/fuel mixture screw in 1/4 -1/2 turn give the throttle a bump and smell again. Or if youre not sure how good it is to start with, buy a kit at the parts store for 25$ and rebuild it. Not really difficult if you can pay attention
MSEE
Joined: Apr 2004
Posts: 10,386
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From: Austin, TX
It's probably a stuck choke; when the motor is warm pull off the air cleaner and make sure the choke plate is fully open. Here's some free advice - don't let friends who don't know what they're doing work on your truck, especially when it comes to carburetors.
Post Fiend
Joined: Apr 2008
Posts: 8,261
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From: Big Sky Country
You can always install a manual choke, 10 bucks and 30 minutes later you're done, you choke it WHEN you need it, IF you need it and for how LONG you need it, i run a manual choke on all my rigs, i just like the mechanics of it and the control it gives me.
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Well, I put the choke setting to lean, the choke is open when it warms up then if you give it a little gas it will stall out.
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Mountain Pass
Joined: May 2009
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From: 40min from Charlotte NPD.
My biggest problem with electric choke is when you restart after sitting for 15min or so, the choke has cooled but the engine is still warm. An electric choke will choke your engine when it doesn't need it.
Oh and sorry ROTLD13 no ideas here, all I know is Holley 4160's. But don't get discouraged there are many knowledgeable people here at FTE, and welcome to the community.
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MSEE
Joined: Apr 2004
Posts: 10,386
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From: Austin, TX
With the truck shut off, look down the throat of the carburetor and pull the throttle back. You should see a stream of gas shoot out the side of the throttle bore toward the venturi.
If you do not see this, we will investigate further.
If you do see this, we will check for vacuum leaks.
If you do not see this, we will investigate further.
If you do see this, we will check for vacuum leaks.
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plugs are new. fuel pump, I don't know how old it is but it seems to be working but I do have a new one coming in. Filters are new. Accelerator pump, How would I check that? Air filter OK, bowl vent plugged maybe.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
The accelerator pump that shane is mentioning is what I was having you check. You saw the gas, so it's OK.
The next thing you need to look for is vacuum leaks. A vacuum leak causes a severe lean condition which exhibits problems similar to what you are seeing. What you need to do is idle the motor, and use a can of carburetor cleaner spray to check for leaks. You do this by spraying suspect areas with the can, and listening for a jump in idle speed. If the idle jumps, that means the area you sprayed took in carburetor cleaner, which means it's leaking. This is how you identify a vacuum leak. Suspect areas include old vacuum lines, brake booster, carburetor base, intake manifold flange, and anywhere else a vacuum signal is present.
When you do this, lean out the idle mixture so that the engine barely runs. This will make the jump in idle very easy to hear. If you do this test with the motor idling normally, sometimes it's hard to hear the jump in idle. That's why it's best to lean out the idle first. When you're done, set the idle back.
The next thing you need to look for is vacuum leaks. A vacuum leak causes a severe lean condition which exhibits problems similar to what you are seeing. What you need to do is idle the motor, and use a can of carburetor cleaner spray to check for leaks. You do this by spraying suspect areas with the can, and listening for a jump in idle speed. If the idle jumps, that means the area you sprayed took in carburetor cleaner, which means it's leaking. This is how you identify a vacuum leak. Suspect areas include old vacuum lines, brake booster, carburetor base, intake manifold flange, and anywhere else a vacuum signal is present.
When you do this, lean out the idle mixture so that the engine barely runs. This will make the jump in idle very easy to hear. If you do this test with the motor idling normally, sometimes it's hard to hear the jump in idle. That's why it's best to lean out the idle first. When you're done, set the idle back.