Turnburn720 Posted April 23, 2020 Share Posted April 23, 2020 Alright fellers I have an 83 f150 with a carburated 300 six here. It died twice when going uphill within 2 days, and then refused to start again. It will run (roughly) for a second or two when I pour a little gas into the carb, then die. I figured it was the fuel pump, so I replaced the mechanical fuel pump, the fuel filter, and blew out the line in between them. Still no fuel, the starter will turn it but it won't run. The rubber hose going to the tank was empty when I pulled it off the old pump, but it was sitting for a while, so I figured it drained back to the tank. I poured a little gas in the rubber hose thinking it might prime it up a little bit I got nothing. I also noticed that the choke plate was fully closed when I took the air filter housing off, and if I reset it by hand, when the throttle cable pulls it shut completely again. Is this normal? I'm a total novice to carburetors so if anyone's got any advice or insight I'd love to hear it. I was thinking that my next step would be to replace the rubber hose between the pump and the hard line running back to the tank, in case the ethanol swelled it up or something. The gas gauge doesn't work, but to my knowledge it has at least a few gallons in the tank. If the hose replacement doesn't make any difference, which direction do I head? Do I look at the carburator, or do I begin the process of removing the bed to look at the tank? Edit: Replaced the rubber hoses, they turned out to be 5/16" Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 23, 2020 Share Posted April 23, 2020 If the engine hasn't been run in an hour or so the choke should be closed. But if you aren't getting fuel then the problem is between the tank and the pump. There's a rubber hose from the tank to the hard line, and if you have two tanks there's another hose from the hard line to the switching valve, then another from the valve to the hard line. And then the hose from the hard line to the fuel pump that you mentioned. The original material does NOT like ethanol. When I got Dad's truck one of those hoses dripped fuel when the truck was off. The line didn't really have a hole in it, it had just turned to sponge. When I pulled it off I mashed it into a ball and it stayed! But if they can leak fuel out they'll leak air in, and that air can kill the vacuum that the pump creates to move fuel. So I'd replace all of the hoses. However, I also had one that wouldn't prime, so I pressurized the fuel fill to the tank with just a few psi of air. That got fuel to the pump and after that all was good, it never failed again. Link to comment Share on other sites More sharing options...
Turnburn720 Posted April 23, 2020 Author Share Posted April 23, 2020 If the engine hasn't been run in an hour or so the choke should be closed. But if you aren't getting fuel then the problem is between the tank and the pump. There's a rubber hose from the tank to the hard line, and if you have two tanks there's another hose from the hard line to the switching valve, then another from the valve to the hard line. And then the hose from the hard line to the fuel pump that you mentioned. The original material does NOT like ethanol. When I got Dad's truck one of those hoses dripped fuel when the truck was off. The line didn't really have a hole in it, it had just turned to sponge. When I pulled it off I mashed it into a ball and it stayed! But if they can leak fuel out they'll leak air in, and that air can kill the vacuum that the pump creates to move fuel. So I'd replace all of the hoses. However, I also had one that wouldn't prime, so I pressurized the fuel fill to the tank with just a few psi of air. That got fuel to the pump and after that all was good, it never failed again. Ok thanks. A guy I was talking to said something about the pickup in the tank, but I thought that the fuel line basically goes into a sock in the tank, there wasn't any valves or anything in there? I'll replace the rubber hoses, is that just 3/8 fuel line? Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 23, 2020 Share Posted April 23, 2020 Ok thanks. A guy I was talking to said something about the pickup in the tank, but I thought that the fuel line basically goes into a sock in the tank, there wasn't any valves or anything in there? I'll replace the rubber hoses, is that just 3/8 fuel line? You need to get ethanol-proof hose. Modern fuel hose is. And I do think it is 3/8". But, there is a sock in the tank and it can get plugged. The old mechanic's trick is to put air pressure on the line going in and blow the sock off. It is more like a strainer than a filter and it might catch flys, but not much more. However, pull the cap off the tank when you do that. Link to comment Share on other sites More sharing options...
Turnburn720 Posted April 23, 2020 Author Share Posted April 23, 2020 You need to get ethanol-proof hose. Modern fuel hose is. And I do think it is 3/8". But, there is a sock in the tank and it can get plugged. The old mechanic's trick is to put air pressure on the line going in and blow the sock off. It is more like a strainer than a filter and it might catch flys, but not much more. However, pull the cap off the tank when you do that. Thanks a lot if the rubber hoses don't work, then I'll give er a good blowin Link to comment Share on other sites More sharing options...
1986F150Six Posted April 23, 2020 Share Posted April 23, 2020 Thanks a lot if the rubber hoses don't work, then I'll give er a good blowin If you blow the sock off, be sure to add an inline fuel filter between the hard line and the fuel pump. Link to comment Share on other sites More sharing options...
Turnburn720 Posted April 23, 2020 Author Share Posted April 23, 2020 If you blow the sock off, be sure to add an inline fuel filter between the hard line and the fuel pump. Yeah that's a good idea Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 23, 2020 Share Posted April 23, 2020 If you blow the sock off, be sure to add an inline fuel filter between the hard line and the fuel pump. Yes!!! I should have said that. And, you can do it even if you don't blow the sock off. Link to comment Share on other sites More sharing options...
Frank Wyatt Posted April 23, 2020 Share Posted April 23, 2020 Ok thanks. A guy I was talking to said something about the pickup in the tank, but I thought that the fuel line basically goes into a sock in the tank, there wasn't any valves or anything in there? I'll replace the rubber hoses, is that just 3/8 fuel line? I have a '81 with the 300/4.9 and Carter YFA carb and all my fuel lines are 5/16 from the tanks all the way to the carb. Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 23, 2020 Share Posted April 23, 2020 I have a '81 with the 300/4.9 and Carter YFA carb and all my fuel lines are 5/16 from the tanks all the way to the carb. Frank - That's good to know. This is something that is frequently asked, and somehow we need to determine what the size(s) are. However, the screen grabs below are from the MPC, with "9324" being the base part # for fuel line. So, what do we make of this? I see both 5/16" and 3/8" used. Link to comment Share on other sites More sharing options...
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