Ok,
I've got a Motorcraft 2150 that is a reman put on by the previous owner. Never seemed to run right. Always ran a bit rich (or not at all) no matter what I did. And...wow..what a hard start. So I decided to pull the top off the carb to see if there was any gas in the float bowl. When i checked there was a very minimal amount...probably less than 1/8 of an inch. The float valve was definately open. So...what does this mean? Its very very clean inside. Does it need a rebuild? What is making the gas leak out of the bowl after a few days?

Thanks in advance.

(82 F150, 351M, Auto)

 

The low fuel level in the bowl means the float height is adjusted incorrectly. I am assuming you checked the level right after the engine was ran, or while the engine was idling. because if the carb sat for a few days, maybe the gas leaked out instead. Anyway, assuming you meant that there was only 1/8" of fuel right after you shut the engine off, this alone will not cause a rich condition. It will cause a lean condition instead. I'm surprised it runs at all with only 1/8 inch of fuel in the bowl. With the carb already installed on the engine, the best way to reset the float height is by a "wet check."

Fuel leaking out of the carb after a few days can be several reasons. Can you tell where it is leaking from? It could be a blown power valve, or a crack in the throttle body. It also could be coming from the throttle shaft (very light seeping is somewhat normal).

These signs alone are not what you would do a rebuild for. I'm completely against remanufactured carbs. I have never met one single person in my entire life who ever had a remanufactured carb work out for them, even after tedious tuning and troubleshooting. And while there are some success stories out there, it's not worth risking your cash and handing over your old carb.

 

So your vote would be to purchase a new one?

 

Well, there isn't really such a thing as a "new" 2150. Any 2150 you get from a parts store will be somebody's old core that has been rebuilt. My vote in your situation would be to address the float height issue first. Also identify where the leaking fuel is coming from.

 

Ok...so don't buy a "new" old one.....didn't really want to spend that $250 anyway.

So, whats the best way to figure out where the gas is leaking out of?

 

Do you for sure know gas is leaking out? Do you see the gas physically seeping out? Or are you assuming it is escaping because of how little gas you find in the fuel bowl? A low fuel bowl level alone means improper float height (generally).

However, if you do see gas seeping out onto the intake, a careful visual inspection is the best way to determine the culprit. A leaking power valve can cause gas to leak from underneath the front of the carb. However, this is hard to tell since most of the power valve housing is hidden while the carb is on the engine. The accelerator pump seal on the front of the carb could contribute to a leak, but this is very unlikely since it is sealed internally by an umbrella valve. There is another small opening between the accelerator pump and the fuel bowl, but it is a very very tiny one. The only other thing I could think of would be a crack in the throttle body casting itself.

In any case, see if you have a leak at all first. Because if your float height is set way low, that means you have that 1/8" in the fuel bowl the entire time it's running. That would be a major reason why you are having driveability issues.