billybooster
10-31-2003, 02:15 AM
Product: Motorcraft 4300/4350
Symptoms:
1. At idle, high revs, including 'down hill off-the-gas...way too high
2. during acceleration, at a certaim point engine seems to choke up and lose power
3. during normal 50-60 mph seems fine
Carb observations
1. Looking at the carb from the front, there is a rod, with a screw thread protruding on the right, that is attached to the throttle cable linkage. This screw threaded rod is attached to the carb near the top right. When the throttle is pulled, it in turn rotates an area 'top right'. This area at the top right seems to 'stick', causing the higher than required revs. It is not related to the throttle cable but the mechanism itself 'inside' the carb. I know this because, if I push/pull on this linkage it reduces the revs and they stay there. Is there any way of 'helping' this linkage reduce the revs, so to speak. I have tried to reduce the pressure from the nut on the screw-threaded linkage but that didnt seem to help.
2. The rear butterfly is intended to open at higher revs..is it controlled mechanically or with a vaccuum? It appears that if I stand over the carb and pull throttle to a 'higher' rev, it doesn't open. What's going on here!!??
So my 4300/4350 seems to provide too much gas...in turn high revs, low mpg.
3. Finally...with the air filter off, looking at the carb from the front, there is, on the left hand front most corner a 'vent hole' or something that looks like it should have a tube/pipe/something attached. It just sits there, unattached. What? Why How who?
Haynes doesn't get specific enough about this and I'm a complete idiot wrt anything like this.
Help greatfully received....thankyou
Symptoms:
1. At idle, high revs, including 'down hill off-the-gas...way too high
2. during acceleration, at a certaim point engine seems to choke up and lose power
3. during normal 50-60 mph seems fine
Carb observations
1. Looking at the carb from the front, there is a rod, with a screw thread protruding on the right, that is attached to the throttle cable linkage. This screw threaded rod is attached to the carb near the top right. When the throttle is pulled, it in turn rotates an area 'top right'. This area at the top right seems to 'stick', causing the higher than required revs. It is not related to the throttle cable but the mechanism itself 'inside' the carb. I know this because, if I push/pull on this linkage it reduces the revs and they stay there. Is there any way of 'helping' this linkage reduce the revs, so to speak. I have tried to reduce the pressure from the nut on the screw-threaded linkage but that didnt seem to help.
2. The rear butterfly is intended to open at higher revs..is it controlled mechanically or with a vaccuum? It appears that if I stand over the carb and pull throttle to a 'higher' rev, it doesn't open. What's going on here!!??
So my 4300/4350 seems to provide too much gas...in turn high revs, low mpg.
3. Finally...with the air filter off, looking at the carb from the front, there is, on the left hand front most corner a 'vent hole' or something that looks like it should have a tube/pipe/something attached. It just sits there, unattached. What? Why How who?
Haynes doesn't get specific enough about this and I'm a complete idiot wrt anything like this.
Help greatfully received....thankyou