NewEnglandF250 Posted June 10, 2020 Share Posted June 10, 2020 Hey folks I really need some help here..... finally after 2 year’s I got my truck going took it out for 190 mile trip and after about 90 miles the truck with started intermittently cutting out upon deceleration after being under load....it keeps going but it seems like the truck shuts off for a split second......it has a YFA and I rebuilt it... new plugs, wires, cap, rotor, fuel filter, gas tank......thanks!!! Link to comment Share on other sites More sharing options...
1986F150Six Posted June 10, 2020 Share Posted June 10, 2020 With the engine cut off, remove the air cleaner and look down into the carburetor throat as you move the throttle cable. Do you see a stream of gasoline being squirted? Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 10, 2020 Share Posted June 10, 2020 With the engine cut off, remove the air cleaner and look down into the carburetor throat as you move the throttle cable. Do you see a stream of gasoline being squirted? Yes, it could be a fuel problem, like David is suggesting. And if so it could easily be a bad fuel pump or something as simple as rotten fuel hoses. There are short sections of hose from the tank to the steel fuel line and from that line to the pump. And if you have dual tanks there are sections from the steel lines to the switching valve. I've had significant problems with those hoses getting so bad that they leaked fuel when the truck wasn't running and leaked air in when it was running. And the air kills the vacuum the pump uses to move fuel. Or, it could be electrical, as in the ignition module or the pickup in the distributor. But one thing at a time - check out the fuel system. Link to comment Share on other sites More sharing options...
NewEnglandF250 Posted June 11, 2020 Author Share Posted June 11, 2020 Yes, it could be a fuel problem, like David is suggesting. And if so it could easily be a bad fuel pump or something as simple as rotten fuel hoses. There are short sections of hose from the tank to the steel fuel line and from that line to the pump. And if you have dual tanks there are sections from the steel lines to the switching valve. I've had significant problems with those hoses getting so bad that they leaked fuel when the truck wasn't running and leaked air in when it was running. And the air kills the vacuum the pump uses to move fuel. Or, it could be electrical, as in the ignition module or the pickup in the distributor. But one thing at a time - check out the fuel system. Thank you very much gentlemen! Link to comment Share on other sites More sharing options...
1986F150Six Posted June 11, 2020 Share Posted June 11, 2020 Thank you very much gentlemen! My response was based on the fact that the carburetor has recently been rebuilt and the stumble [power loss] is reportedly after deceleration. Perhaps the accelerator pump is not functioning correctly? Link to comment Share on other sites More sharing options...
FuzzFace2 Posted June 11, 2020 Share Posted June 11, 2020 My response was based on the fact that the carburetor has recently been rebuilt and the stumble [power loss] is reportedly after deceleration. Perhaps the accelerator pump is not functioning correctly? This is going to be a hard one as I under stand the motor does not shut off and stay off but shuts off and then back on when you let off the throttle. Take it no tack in the in the truck? Maybe you could pick up a cheap one and just lay it some where and when this happens see if the tach is showing RPM or not. Dave ---- Link to comment Share on other sites More sharing options...
NewEnglandF250 Posted June 12, 2020 Author Share Posted June 12, 2020 With the engine cut off, remove the air cleaner and look down into the carburetor throat as you move the throttle cable. Do you see a stream of gasoline being squirted? So I check the rubber between the steel lines and the seemed ok but I replaced them any way. Put a new fuel filter in. I cranked it Iver and was getting fuel but just a trickle, would definitely not call it a stream. I had my buddy crank it over and I noticed some fuel coming out of the pump at the seam connecting the top & bottom. I have a new one coming this morning so fingers crossed!!! Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 12, 2020 Share Posted June 12, 2020 So I check the rubber between the steel lines and the seemed ok but I replaced them any way. Put a new fuel filter in. I cranked it Iver and was getting fuel but just a trickle, would definitely not call it a stream. I had my buddy crank it over and I noticed some fuel coming out of the pump at the seam connecting the top & bottom. I have a new one coming this morning so fingers crossed!!! Yes, lets hope that's the problem. But also check your oil. Does it smell like gas on the dip stick? A bad fuel pump can put gas in the oil and cause problems with the engine's bearings. Link to comment Share on other sites More sharing options...
NewEnglandF250 Posted June 12, 2020 Author Share Posted June 12, 2020 This is going to be a hard one as I under stand the motor does not shut off and stay off but shuts off and then back on when you let off the throttle. Take it no tack in the in the truck? Maybe you could pick up a cheap one and just lay it some where and when this happens see if the tach is showing RPM or not. Dave ---- Hey Dave, the only other way I can think to describe it is ...... it’s like flipping a kill switch off and then back on. Link to comment Share on other sites More sharing options...
NewEnglandF250 Posted June 12, 2020 Author Share Posted June 12, 2020 Yes, lets hope that's the problem. But also check your oil. Does it smell like gas on the dip stick? A bad fuel pump can put gas in the oil and cause problems with the engine's bearings. Thanks Gary, spot on!!! It does smell like it has gas in it.... Link to comment Share on other sites More sharing options...
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