I've rebuild a 2100 2bbl carb that is on my 72 F-100 302 engine. The truck was running well, but now when I initially depress the gas pedal the engine bogs down and if you hold it there it will die out in a few seconds. Also if you press the accelerator all the way down, the engine will only last a few seconds then die out.

I also am able to drive it, but only in 1st gear... when you give it anymore gas to get up to speed for 2nd and 3rd gear, they engine bogs down and cuts out... it also does this when braking and preparing to go around turns.

Any advice? I need to get this truck running properly this weekend, because we are moving.

 

Did the problems start right after the rebuild or did it work fine for a while then start having problems? Also, what was the reason for the rebuild in the first place. The bogging usually indicates the accelerator pump isn't working or isn't pumping enough fuel. Let us know a little more about the chain of events.

 

The truck ran fine after the rebuild. The rebuild was performed, because I bought the truck after it had been sitting for years... it only would start and idle when i bought it... the rebuild appeared to fix it, because I drove it for about 3 weeks after with only one problem. That problem was when driving at higher speeds (35-55) in 3rd gear the engine would sometimes out of no where bog down to idle... when I took my foot off the gas for a few seconds, then slowly put my foot back down... and press the gas pedal, the truck would surge a few times, but then get back to running normally.

It appears that the problem I was having at higher speeds is now happening all the time, basically, I can only drive the truck in first gear with a litte bit of pressure on the gas pedal... anything more and the truck bucks and then bogs down... until it chokes itself off.

I can however, start the truck, let it idle ... then rev the engine without a problem... however, when holding it a high rpm, the engine doesn't last that long, before it chokes itself off. After that, I have a very difficult time getting it to restart, mostly I have to let it crank for 15-20 seconds while pumping the gas pedal.

This is really bothering me, because the truck was running fine, but had a strong smell of gas fumes from the exhaust, so I decided to adjust the idle mixture scews... I did that, then drove off and all these problems started. I shouldn't have played with the carburetor, but I thought it might be running rich due to the exhaust fumes, so I adjusted the mixture.

The truck had been sitting for years, so the fuel tank is dirty, but I've been replacing the fuel filter every 3 weeks or so... I am concerned that when adjusting the idle mixture scews ... I dislodged more dirt into the carb.

I also had a leaking accelorator pump gasket yesterday, but I retightened the screws and that stopped.

 

Either the float level is too low or the fuel pump is not pumping enough fuel to keep the bowl full. I would also look for dryrotted fuel lines, especially between the tank and frame. It may not leak fuel, but can suck in air.

 

I agree, sounds like the pump is bad. If you have a fuel pressure gauge, T it into the inlet line for the carb. It should maintain about 6pis. A pound or two either way is OK but it should stay fairly steady at all engine speeds. Good luck.

 

I agree; it sounds like the carb is starving for fuel. The only thing I would add would be to do a wet-check on the float to see how much gas is actually in your fuel bowl.

 

A friend of mine said to pull out the fuel line in the tank to see how bad the end of it is, is it possible that the filter on that end could be really bad???? Remember the truck sat for years... not being driven.