http://theamcforum.com/forum/ This is an XML content feed of; The AMC Forum : 6 Cylinder Engine Repair and Modifications : My MPG is poor Sat, 18 May 2013 07:12:07 +0000 Sat, 07 Feb 2009 16:17:04 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 10.03 360 theamcforum.com/forum/RSS_post_feed.asp?TID=4314 http://theamcforum.com/forum/http://www.theamcforum.com/forum/skin_images_amc/forumheader.png http://theamcforum.com/forum/ http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72815.html#72815 Author: farna
Subject: 4314
Posted: Feb/07/2009 at 4:17pm

You can hook a generic "stretch" spring from a hardware store to the linkage and something else on the motor. Just don't get one very stiff or you'll tire your foot out holding the throttle open. ]]> Sat, 07 Feb 2009 16:17:04 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72815.html#72815 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72810.html#72810 Author: poormansMACHINE
Subject: 4314
Posted: Feb/07/2009 at 3:49pm

WD 40 doesn't fix old rusted/fatigued springs. Take it to an an auto parts store.
If it's rusted enough to snap, you'll have other problems like the pedal staying down.
]]> Sat, 07 Feb 2009 15:49:58 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72810.html#72810 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72803.html#72803 Author: Bake
Subject: 4314
Posted: Feb/07/2009 at 3:12pm

poormansMACHINE wrote: External on the linkage.

this must be the one right in on the linkage right in front of the firewall. Looked pretty rusty. I can't find anything about that one in the TSM. Would I get it at an auto store or some other kind of spring place?

I sprayed some WD-40 on it and it seems like that might have stopped the sticking.

]]> Sat, 07 Feb 2009 15:12:49 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72803.html#72803 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72399.html#72399 Author: poormansMACHINE
Subject: 4314
Posted: Feb/04/2009 at 11:03pm

External on the linkage.]]> Wed, 04 Feb 2009 23:03:14 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72399.html#72399 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72394.html#72394 Author: Bake
Subject: 4314
Posted: Feb/04/2009 at 10:48pm

poormansMACHINE wrote: Cheap and easy enough to swap out.

is that external or under the round cap thing on the front?
]]> Wed, 04 Feb 2009 22:48:49 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72394.html#72394 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72367.html#72367 Author: poormansMACHINE
Subject: 4314
Posted: Feb/04/2009 at 9:38pm

Cheap and easy enough to swap out.]]> Wed, 04 Feb 2009 21:38:32 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72367.html#72367 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72364.html#72364 Author: Bake
Subject: 4314
Posted: Feb/04/2009 at 9:18pm

poormansMACHINE wrote: It may be just as simple as a weak throttle return spring.

which could be exactly what the guy told me it might be.


]]> Wed, 04 Feb 2009 21:18:10 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72364.html#72364 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72359.html#72359 Author: poormansMACHINE
Subject: 4314
Posted: Feb/04/2009 at 8:57pm

It may be just as simple as a weak throttle return spring.]]> Wed, 04 Feb 2009 20:57:06 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72359.html#72359 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72358.html#72358 Author: Bake
Subject: 4314
Posted: Feb/04/2009 at 8:44pm

farna wrote: If it's cold outside the idle going up until you tap it is normal. When the choke starts to close it moves a cam on the throttle linkage that keeps the throttle slightly open. It's called the "fast idle cam" (or something similar). When it's cold, step on the gas once all the way to the floor BEFORE turning the key. Then turn the key and the choke should be "set" (really it's setting the fast idle). As the engine warms up the fast idle will stay in position until the gas pedal is pressed enough to release it, hence the tap of the foot to release the fast idle. If it's on fast idle ALL the time, even when it's warm outside, it could be that the choke is just set too rich. That can cause the problems Thikstik mentioned, along with poor gas mileage. Carburetors are mechanical, they have many moving parts. Sometimes the passages and the holes where the shafts turn just get worn out. At that point the thing can only be replaced, though there are a few shops that specialize in rebuilding antique carbs. This are a couple places: http://www.classicpreservation.com/carbrebuilding.html http://www.wyocarb.com/ Places like this will bore the shaft holes out and insert brass bushings to bring the carb back to specs if necessary. I've heard good things about Wyoming Carb, just found CPC on the net.

it's more when I'm approaching a stop or red light and take my foot off the gas, it's not still at a high idle, you might not even notice anything unless you tap and then it goes even a bit lower idle.
]]> Wed, 04 Feb 2009 20:44:39 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72358.html#72358 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72344.html#72344 Author: farna
Subject: 4314
Posted: Feb/04/2009 at 6:57pm

If it's cold outside the idle going up until you tap it is normal. When the choke starts to close it moves a cam on the throttle linkage that keeps the throttle slightly open. It's called the "fast idle cam" (or something similar). When it's cold, step on the gas once all the way to the floor BEFORE turning the key. Then turn the key and the choke should be "set" (really it's setting the fast idle). As the engine warms up the fast idle will stay in position until the gas pedal is pressed enough to release it, hence the tap of the foot to release the fast idle.

If it's on fast idle ALL the time, even when it's warm outside, it could be that the choke is just set too rich. That can cause the problems Thikstik mentioned, along with poor gas mileage.

Carburetors are mechanical, they have many moving parts. Sometimes the passages and the holes where the shafts turn just get worn out. At that point the thing can only be replaced, though there are a few shops that specialize in rebuilding antique carbs.
This are a couple places:
http://www.classicpreservation.com/carbrebuilding.html
http://www.wyocarb.com/

Places like this will bore the shaft holes out and insert brass bushings to bring the carb back to specs if necessary. I've heard good things about Wyoming Carb, just found CPC on the net.

]]> Wed, 04 Feb 2009 18:57:24 +0000 http://theamcforum.com/forum/my-mpg-is-poor_topic4314_post72344.html#72344