Won't return to idle
Thread Starter
|
New User
Joined: Aug 2011
Posts: 3
Likes: 0
Won't return to idle
Stats:
1982 Ford F-150 m/t 4x4 120k mi
4.9L (300) in-line 6
Carb was just freshly rebuilt by me (and I am VERY much an amateur). The reason I rebuilt it is it was running so rich that it would blow unspent fuel out the exhaust in puddles. RPM had to be kept at least at 1600-1800 for it to idle. When I rebuilt the carb, I found out the idiot I had let "rebuild" it before for me had installed the point backwards...
Fixed this problem, she doesn't seem to be running so rich now. Set the idle between 800-900, truck maintains idle - doesn't die, seems to run just as smooth as she did when I was a kid (my dad owned this truck since 1992). Now I have a new set of problems. The biggest that I see right now is that it will not return to idle once the throttle is opened. See the video here:
Also when I went to start the truck the choke didn't set right. Did not start until manually set the choke at the carb. Video here:
Any help or advice would be much appreciated. I can go take more video or pictures if you need to see something else to help.
1982 Ford F-150 m/t 4x4 120k mi
4.9L (300) in-line 6
Carb was just freshly rebuilt by me (and I am VERY much an amateur). The reason I rebuilt it is it was running so rich that it would blow unspent fuel out the exhaust in puddles. RPM had to be kept at least at 1600-1800 for it to idle. When I rebuilt the carb, I found out the idiot I had let "rebuild" it before for me had installed the point backwards...
Fixed this problem, she doesn't seem to be running so rich now. Set the idle between 800-900, truck maintains idle - doesn't die, seems to run just as smooth as she did when I was a kid (my dad owned this truck since 1992). Now I have a new set of problems. The biggest that I see right now is that it will not return to idle once the throttle is opened. See the video here:
Also when I went to start the truck the choke didn't set right. Did not start until manually set the choke at the carb. Video here:
Any help or advice would be much appreciated. I can go take more video or pictures if you need to see something else to help.
Thread Starter
|
New User
Joined: Aug 2011
Posts: 3
Likes: 0
Choke fixed (I think)
I went out and adjusted it, the coiled spring inside was not putting any pressure on the idle cam or the choke so there was no reason for the choke to close. Got it adjusted now so when the throttle gets open that coil exerts pressure and drops the cam so the fast idle screw rests on it and the choke plate closes!! WOO HOO! Have to wait until the engine cools to see if it is all adjusted right. Warmed up enough that she wouldn't start choked for me to double check it.
Now it's just the return to idle. Linkage to the pedal is also the sole "return spring". Is it possible it's just not enough after 29 years? I'm thinking about just adding some sort of extra spring to just snap that sucker closed once I let off the pedal....how bad an idea is this?
Now it's just the return to idle. Linkage to the pedal is also the sole "return spring". Is it possible it's just not enough after 29 years? I'm thinking about just adding some sort of extra spring to just snap that sucker closed once I let off the pedal....how bad an idea is this?
Thread Starter
|
New User
Joined: Aug 2011
Posts: 3
Likes: 0
Timing: No clue.
Check for leaks? Yeah, all over the place, haven't found any, but this is what I did find...
Ok, I took the carb off the truck, because I thought the screw on the pump link arm might have been catching and causing problems. Figured out that the throttle solenoid is catching the idle assembly before it returns all the way to idle. See pics here.
See how the idle screw is not contacting the side of the carb where it's supposed to stop, but that arm is contacting the solenoid and stopping it??? Not sure what's going on there, or how to fix it.
I don't know how to adjust that solenoid thing aside from to add shims to where it attaches to the carb body.
Check for leaks? Yeah, all over the place, haven't found any, but this is what I did find...
Ok, I took the carb off the truck, because I thought the screw on the pump link arm might have been catching and causing problems. Figured out that the throttle solenoid is catching the idle assembly before it returns all the way to idle. See pics here.
See how the idle screw is not contacting the side of the carb where it's supposed to stop, but that arm is contacting the solenoid and stopping it??? Not sure what's going on there, or how to fix it.
I don't know how to adjust that solenoid thing aside from to add shims to where it attaches to the carb body.
Elder User
Joined: Apr 2009
Posts: 725
Likes: 2
I think that's called the anti stall solinoid, basically it keeps that throttle from closing too quickly and killing the motor. Should be able to loosen that nut (its a jamb nut if i remember correctly) that place it where you want, then retighten.
If this was never moved you might have something else out of adjustment, this is why i asked about timing. If your timing it too far advanced its going to make it difficult to set your idle speed as low as it should be (550-600rpm for a manual, 800-900 for auto trans). Set your base timing to 10*-12* BTDC and reset your idle. That should put you in the ball park for factory specs.
If this was never moved you might have something else out of adjustment, this is why i asked about timing. If your timing it too far advanced its going to make it difficult to set your idle speed as low as it should be (550-600rpm for a manual, 800-900 for auto trans). Set your base timing to 10*-12* BTDC and reset your idle. That should put you in the ball park for factory specs.
Thread
Thread Starter
Forum
Replies
Last Post
cstephens
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
6
Feb 18, 2018 07:49 PM
schiff94
1961 - 1966 F-100 & Larger F-Series Trucks
9
Mar 6, 2015 07:34 AM
JOGR
1967 - 1972 F-100 & Larger F-Series Trucks
1
Jul 17, 2014 11:15 PM
Danny Stroup
1973 - 1979 F-100 & Larger F-Series Trucks
15
Jan 16, 2010 05:27 PM
