I just rebuilt the Motorcraft 2150 on my 1979 Ford F 150 and it runs great except when cold starting.


I am sure the choke, fast idle, regular idle and idle mixture screws are all set correctly.


The issue seems to be with my accelerator pump. When I start the truck, I either have to pump the crap out of it and turn it over forever, or I can manually depress the accelerator pump a couple of times and she fires right up and runs great.


Once it is started, the fast idle works (I can disengage it by blipping the accelerator) and the choke opens when it warms up, etc.


Seems like when I manually pull the throttle linkage all the way open it will actuate the accelerator pump the first time, but doesn't after that. (If that makes sense)...


The only other piece of the puzzle is that I installed a new fuel filter between the carb and fuel pump and I suspect it may be too small. I wanted a clear fuel filter, so I just picked one out. In researching this issue, I have seen that other filters of this type on similar vehicles were larger than mine.


I did replace the little bearing and rod, and the diaphragm, etc. for the accelerator pump when I did the rebuild.


Also, I put the linkage for the accelerator pump rod in the third hole from the bottom.


Any thoughts would be appreciated. Thanks in advance.

 

Maybe blockage in the accelerator pump passages? But it runs great after it starts and I did spray the passages out when I rebuilt.
That's why I was wondering about the fuel filter. I guess my next test will be to relocate the filter to before the fuel pump or just take it out of the equation to see if there is a difference.

 

If the accelerator pump is not working, you should also experience a hesitation will taking off from a stop.

 

Good point. I will take note this weekend to see. I am wondering if I got the right pump with my carb kit. My carb doesn't have a tag so I had to guess on the kit. I noticed the replacement pump had a two piece rod for the accelerator pump instead of one like the original.