4300 carb help

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cdn_73mach1

Member
Joined
May 25, 2013
Messages
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Location
Canada
My Car
1973 mach 1 351 c, 4 spd - medium copper metalic, standard interior
I have a 73 mach 1 q code engine with the 4300 carb. Someone rebuilt the carb and it ran well a few days. Now I am getting fuel shooting out the top of the carb. It is shooting up the float bowl vents. I believe this means that the floats need to be adjusted?

I have the ford shop manuals but can't find any specs on the height setting of the floats. Does anyone know the height for the 73?

 
try this 1st disconnect the fuel line from the carb and plug it off. Start the engine and let it run out of fuel. Connect the fuel line, start it and see if it still floods.

You may just have a piece of trash in the needle valve...sometimes, that will wash it out.

 
+1 @ Don. Check out the link below for dry float settings. If you had a 2100 or 2150 I could help you all day, sorry the best I can do is pass a link. You MIGHT (probably not), but might need a new float but it's probably just junk in there or the wet float is too high.

http://www.ford-trucks.com/forums/204005-autolite-4300-float-adjustment.html
Thanks for the tips Don and Rutkak. This morning I tried that, removing the gas line and running until it quit. When I hooked up the line again it wouldn't really run and shot the gas out the vents again.

I had a look at the link for the float settings. Would the float settings be the same for all 4300's even for different years? I found a link also to the settings for a 68 4300 and it said 25/32 float height. I have never taken a carb apart so this is all new to me.

 
+1 @ Don. Check out the link below for dry float settings. If you had a 2100 or 2150 I could help you all day, sorry the best I can do is pass a link. You MIGHT (probably not), but might need a new float but it's probably just junk in there or the wet float is too high.

http://www.ford-trucks.com/forums/204005-autolite-4300-float-adjustment.html
Thanks for the tips Don and Rutkak. This morning I tried that, removing the gas line and running until it quit. When I hooked up the line again it wouldn't really run and shot the gas out the vents again.

I had a look at the link for the float settings. Would the float settings be the same for all 4300's even for different years? I found a link also to the settings for a 68 4300 and it said 25/32 float height. I have never taken a carb apart so this is all new to me.
You might find some help here.

 
+1 @ Don. Check out the link below for dry float settings. If you had a 2100 or 2150 I could help you all day, sorry the best I can do is pass a link. You MIGHT (probably not), but might need a new float but it's probably just junk in there or the wet float is too high.

http://www.ford-trucks.com/forums/204005-autolite-4300-float-adjustment.html
Thanks for the tips Don and Rutkak. This morning I tried that, removing the gas line and running until it quit. When I hooked up the line again it wouldn't really run and shot the gas out the vents again.

I had a look at the link for the float settings. Would the float settings be the same for all 4300's even for different years? I found a link also to the settings for a 68 4300 and it said 25/32 float height. I have never taken a carb apart so this is all new to me.
You might find some help here.
That is good to know Tommy, nice to see a forum just for ford carbs

 
Classic float is stuck situation.

If you smack the fuel bowl with a screwdriver handle it may knock the float back down, but it will require you you open the carb up and see what is causing the fuel bowl lever to get stuck.

The float might of had a hole in it and filled with gas that can happen.

The float is like a toilet tank shutoff. So when the fuel reaches a set level the float turns off the gas flowing into the carb, its suppose to keep the fuel just at the right level. When it gets stuck there is no metering of the fuel and it fills up and squirts out the vents tubes at 6-8 psi from the fuel pump.

So now you have to figure out why the float is getting stuck open.

 
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