78 Ford "Cold Natured"
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78 Ford "Cold Natured"
hey all,
I have a 78 F150 Ranger and its got a 351M with a Holley 4bbl carb. This is the first carbureted vehicle I've owned. The guy I bought it from says that it is very "cold natured" --- so I have to let it warm up for quite a while before I can run it. Well my father in law says that its not normal for a vehicle to be like that. I usually have to let it warm up for about 5 min. and then its very sluggish when running up until about 10 min. after I've been driving it. But after I've been driving it for a while, it runs like a champ. The ol father in law suggests that i need to tune the carb a little and it will run like brand new. Is this true and if so, how do i go about tuning it? I'm sure you'll need some more info. Just let me know. Thanks in advance.
I have a 78 F150 Ranger and its got a 351M with a Holley 4bbl carb. This is the first carbureted vehicle I've owned. The guy I bought it from says that it is very "cold natured" --- so I have to let it warm up for quite a while before I can run it. Well my father in law says that its not normal for a vehicle to be like that. I usually have to let it warm up for about 5 min. and then its very sluggish when running up until about 10 min. after I've been driving it. But after I've been driving it for a while, it runs like a champ. The ol father in law suggests that i need to tune the carb a little and it will run like brand new. Is this true and if so, how do i go about tuning it? I'm sure you'll need some more info. Just let me know. Thanks in advance.
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1. Does it have an electric or manual choke?
2. Is the choke operational?
3. Are you 'setting the choke' before you start the engine?
4. First thing in the morning before starting the engine, open the air cleaner and check the choke plate. It should be open from the last run. Move the throttle linkage to wide open and release, the plate should close. Does it close all the way?
2. Is the choke operational?
3. Are you 'setting the choke' before you start the engine?
4. First thing in the morning before starting the engine, open the air cleaner and check the choke plate. It should be open from the last run. Move the throttle linkage to wide open and release, the plate should close. Does it close all the way?
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Originally Posted by 76supercab2
1. Does it have an electric or manual choke?
2. Is the choke operational?
3. Are you 'setting the choke' before you start the engine?
4. First thing in the morning before starting the engine, open the air cleaner and check the choke plate. It should be open from the last run. Move the throttle linkage to wide open and release, the plate should close. Does it close all the way?
2. Is the choke operational?
3. Are you 'setting the choke' before you start the engine?
4. First thing in the morning before starting the engine, open the air cleaner and check the choke plate. It should be open from the last run. Move the throttle linkage to wide open and release, the plate should close. Does it close all the way?
2. The choke is operational.
3. I usually start the engine and then set the choke.
4. I'll have to try this out next time i run the truck.
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4 only works if you have an automatic choke.
Since your choke is manual, set it and then check and see if it is closing all the way. There should also be a fast idle cam that engages when the choke is set. Does the idle speed increase with choke on? As the truck warms up, you should be able to ease off the choke. You probably won't be able to go full off until warm, but as it warms up go to 1/4, run some, then 1/3 run some etc.
Since your choke is manual, set it and then check and see if it is closing all the way. There should also be a fast idle cam that engages when the choke is set. Does the idle speed increase with choke on? As the truck warms up, you should be able to ease off the choke. You probably won't be able to go full off until warm, but as it warms up go to 1/4, run some, then 1/3 run some etc.
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There are 3 carb systems you need to make sure are set right.
Idle air/fuel mixture screws
Full Choke Butterfly set to 1/8" gap
Fast Idle circuit linkage correctly adjusted.
http://www.autozone.com/az/cds/en_us...rInfoPages.htm
Idle air/fuel mixture screws
Full Choke Butterfly set to 1/8" gap
Fast Idle circuit linkage correctly adjusted.
http://www.autozone.com/az/cds/en_us...rInfoPages.htm
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Originally Posted by Mil1ion
There are 3 carb systems you need to make sure are set right.
Idle air/fuel mixture screws
Full Choke Butterfly set to 1/8" gap
Fast Idle circuit linkage correctly adjusted.
http://www.autozone.com/az/cds/en_us/0900823d/80/0a/cd/d5/0900823d800acdd5/repairInfoPages.htm
Idle air/fuel mixture screws
Full Choke Butterfly set to 1/8" gap
Fast Idle circuit linkage correctly adjusted.
http://www.autozone.com/az/cds/en_us/0900823d/80/0a/cd/d5/0900823d800acdd5/repairInfoPages.htm
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All the replys you got are good and you should followup on them. I had the same issue, did all that was suggested and she still ran like crap while getting 6.5 MPG. The issue was a huge vacuum leak by the EGR valve port on the manifold. Make sure you have good manifold vacuum and no other external vacuum leaks in hoses or ports. I still need to let her warm up for about 1 minute before driving. Keep in mind I live in FL and it is 90 degrees now.
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