This is probably an easy one for most of you guys. I have inherited a 73 F250 4x4 with the stock 360 and the 2 bbl motocraft carb. The thing loses it's prime every night (or even more often) and I'm trying to figure out why. I've kitted the carb but when I did, I noticed there were 2 vacuum ports (I think) on the rear of the carb with nothing plugged in to them and one on the left front of the float bowl just over the fuel supply intake. It didnt have anything connected to it either. The line from the vacuum advance is intact and running from the the right front of the carb near the bottom near one of the mixture screws to the distributer as it should. This line has a plastic splitter on it with the T capped so it's just a single vacuum line. (Maybe something should be plugged into that "T"?) Anyway, I've replaced the fuel pump, kitted the carburetor as I've mentioned and I still need to manually prime the darn thing to get it started most of the time. Could this be caused by some of these vacuum lines not going to the right places (or no places?) I've capped everything on the back and the one on the front and it still loses it's prime. Once it's started it runs like a dream. Any help with this would be so appreciated. I'm pulling my hair out and don't have much left. Thanks all and Happy Holidays!!

 

When you say it's loosing it's prime do you mean all the fuel is completely gone out of the float bowl ?

 

Actually, losing it's prime may have not been an accurate description of the problem. I don't think the float bowl is empty upon trying a cold start. I do know that there isn't any fuel being squirted down the intake when I first try and start it. It seems to me that there was fuel in the float bowl. I tried starting it this morning without dumping gas down the carb first and it actually did finally start but it darned near killed the battery before it did. Thanks for responding.
Morlogs

 

Is the accelerator pump working? When you press down on the gas pedal there should be two solid streams of fuel squirting down the carb bores.
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That's what I originally thought the problem was too so I kitted the carb (Including Accelerator Pump) but it didn't help the problem. Maybe the pump that came with the kit was bad. (or maybe, just maybe...I did something wrong when I installed it) Although I'd done it several times over the years and it sure seems pretty straight-forward to me. Would you say that's the most likely reason for the problem? If the accelerator pump was bad would there be other symptoms once the engine was running or is that all it does?
Thanks
Morlogs