Hey Guys,
I have a '76 FJ40 with the stock carb, plugged off AI and EGR, condenser in place of igniter, otherwise stock. I rebuilt the carb with Jim Chenoweth's kit (included new float and new secondary diaphragm) about 3 years ago and it has worked great until Thanksgiving weekend at Land-Between-the-Lakes when I noticed it began to miss big time intermittently at anything between idle and full bore pedal to the metal. That is it idled nice and smoothly but at anything off idle it missed unless I really tromped the pedal when I could feel a surge from the accelerator pump jet of fuel and I could feel the second throttle open in 3rd and 4th gears. Being a few hundred miles from home and not looking forward to removing the carb and rebuilding it with 6" of snow in my driveway and temperatures below 20F, I have been adding a bottle of fuel cleaner to each tank of gas and I'm on my 3rd or 4th tank now. The problem of the miss has greatly dimished in the past few days and seems to sort of come and go but I'm not ready to say that it is completely gone. By the way, I could smooth it out when it was missing badly by choking it a little, even with the engine warm. I also tried some carb cleaner spray through the holes in the bowl to try to hit the jets and also inside th throats but I don't think I got it where it needed to go.
My diagnoses is she was/is not getting enough fuel at anything but idle or unless gettting juice from the acclerator pump jet or the secondary jet. I've been hoping the problem was some dirt or varnish build-up in the primary or main jet/circuit which the fuel system cleaner in each tank of gas might clean up and this seems to be working slowly. Could it be something like the power valve or other internal mechanisms I don't really understand malfunctioning? Doesn't it seem a little soon, 3 years or so, to have to rebuild the carb? By the way, the fuel level in the site glass is right where it should be, even when she was missing badly, and I did a full tuneup last summer (valve adjustment, new cap-rotor-points-condenser-plugs-plugwires, set dwell and timing, new pcv, air and fuel filters). It's been getting me back and forth to work OK and whatever the problem was may have been cured by now but interested in your thoughts. I'd really like to avoid having to remove th ecarb and properly rebuilding it until spring/summer.
Thanks,
Pete
I have a '76 FJ40 with the stock carb, plugged off AI and EGR, condenser in place of igniter, otherwise stock. I rebuilt the carb with Jim Chenoweth's kit (included new float and new secondary diaphragm) about 3 years ago and it has worked great until Thanksgiving weekend at Land-Between-the-Lakes when I noticed it began to miss big time intermittently at anything between idle and full bore pedal to the metal. That is it idled nice and smoothly but at anything off idle it missed unless I really tromped the pedal when I could feel a surge from the accelerator pump jet of fuel and I could feel the second throttle open in 3rd and 4th gears. Being a few hundred miles from home and not looking forward to removing the carb and rebuilding it with 6" of snow in my driveway and temperatures below 20F, I have been adding a bottle of fuel cleaner to each tank of gas and I'm on my 3rd or 4th tank now. The problem of the miss has greatly dimished in the past few days and seems to sort of come and go but I'm not ready to say that it is completely gone. By the way, I could smooth it out when it was missing badly by choking it a little, even with the engine warm. I also tried some carb cleaner spray through the holes in the bowl to try to hit the jets and also inside th throats but I don't think I got it where it needed to go.
My diagnoses is she was/is not getting enough fuel at anything but idle or unless gettting juice from the acclerator pump jet or the secondary jet. I've been hoping the problem was some dirt or varnish build-up in the primary or main jet/circuit which the fuel system cleaner in each tank of gas might clean up and this seems to be working slowly. Could it be something like the power valve or other internal mechanisms I don't really understand malfunctioning? Doesn't it seem a little soon, 3 years or so, to have to rebuild the carb? By the way, the fuel level in the site glass is right where it should be, even when she was missing badly, and I did a full tuneup last summer (valve adjustment, new cap-rotor-points-condenser-plugs-plugwires, set dwell and timing, new pcv, air and fuel filters). It's been getting me back and forth to work OK and whatever the problem was may have been cured by now but interested in your thoughts. I'd really like to avoid having to remove th ecarb and properly rebuilding it until spring/summer.
Thanks,
Pete