I've got a 1979 F250 with the 300 straight 6. I have been having a problem with it flooding bad sometimes. Everytime it has happend it has been sitting overnight and the outside temp is cold (about 25 or colder). I think cold may have somthing to do with it because today it is about 35 and it started not a problem. When it does flood its bad. It backfires while trying to start and is real difficult to get started.
Does anybody have any idea what could be causing this? I just replaced the carb with a rebuilt one about a month ago.

 

sounds like maybe a choke issue?

 

I think the choke is working right. It closes all the way and seems to open in the right amount of time. The only other problem I have had is that it bucks/ jerks if you dont let it warm up for 5 min or so before taking off. I dont think the problems are related though

 

Man that is strange, especially with it being 25 degrees outside. Heck man I'd be happy if my truck started at all, let alone backfired, after being flooded. For now you should park your car somewhere higher up and long-term you should probably get another place and just drive to the lake on the weekends. Hope that helps.

 

Have you adjusted the rebuilt carb? I have heard of several people having issues with rebuilt or reman carbs and most of their problems went back to the unit not being adjusted properly. Hope this helps.

 

Well this is my daily driver so just driving it on weekends wolnt work.

And as far as it being adjusted correct. I think it is seems to idle good at both cold and warm idle speeds and I even had the local garage check to see that the fuel mixture was correct.

I have not had the problem all this week but the temps have been in the 40's. I bet it will start back up right as soon as the cold comes next week.

 

I am no expert just offering a possibility. Could you have a small amount of water in your fuel sytem that has gotten into the carb and freezes keeping the needle from seating. I noticed that you said it didn't happen at temps around 35.but it did at 25. How long does the flooding last? Is it just on intial start or for the first few minutes?

 

The water could be an idea but im guessing that would go away after a tank of gas or so. I'd say the flooding is just on the initial start its real hard to get it started but once it gets going it runs good.

 

My 300 does the exact same thing. Takes forever to start. Well I should say its hard to start and does backfire but ain't had it flood out yet. It also bucked if you don't let itt run for 5 min or so. I'm solving the problem and putting a 390 in it haha