Close



Results 1 to 5 of 5
  1. #1
    FEP Member mcavalear's Avatar
    Join Date
    Sep 2010
    Location
    Holly Springs NC
    Posts
    110

    Default Light throttle hesitation

    My 82 has sat for about 8 years. I recently disassembled my 4160, thoroughly cleaned it, and replaced all of the gaskets. It runs well except for when you feather the throttle it hesitates and then clears up. This is what I'm running:

    Stock block and heads. No idea about the internals but nothing high performance.
    65 primary jets
    6.5 power valve
    31 accelerator pump nozzle
    orange pump cam
    idle mix screws out 1 1/2 turns

    car has 20" of vacuum at idle
    14 initial timing and about 30 at full advance

    Where should I start tuning?
    82 Capri T-Tops

  2. #2
    FEP Senior Member
    Join Date
    May 2016
    Location
    Lake City Pa 16423
    Posts
    510

    Default

    Sounds like the accelerator pump is not giving enough fuel squirt at light throttle movements. You can check this by removing the air cleaner and moving the throttle linkage by hand a very small amount and see if the squirters are putting out. If not, then check the accelerator pump camp for wear and the pump arm adjustment when throttle is wide open. You have a lean out condition causing the light bog.

  3. #3

    Default

    Which 4160? What's the LIST-XXXX number on the front of the choke shroud? Having sat 8 years, and only re-gasket-ed, start with float/fuel levels (to see that needles and seats (and floats) are doing their jobs). Start and warm engine up to operating/thermostat temperature. Could be lean off-idle, could be rich. "Feathering" just off-idle indicates an issue with the primary idle/transition circuits. Remove the float bowl sight plugs from the passenger side of the float bowls. If gas runs out (too high) etc., shut the engine off and adjust the needles and seats (big flat screwdriver and 5/8 wrench - loosen screw, turn wrench clockwise) down say 1/2 turn, or whatever is necessary so fuel isn't running out all over the place. Set primary and secondary float/fuel levels to the bottom edge of the threaded hole (clockwise to lower fuel level with 5/8 wrench, and vice versa) of the float bowl sight plugs' holes. Set idle speed, in gear with blocked wheels if the car has an automatic transmission. Otherwise, if the car has a standard transmission, set idle speed in neutral. Keeping your 1-1/2 turns out of the idle mixture screws in mind, slowly turn each in clockwise, keeping track of each 1/4 or 1/8 turn, until the engine slows/roughens a bit, then back out 1/4 turn. Repeat on each mixture screw. Readjust idle speed if it changed some. Where the mixture screws end up, like at 1-1/2, or 3/4, or wherever, for best, leanest (most inward), smoothest (highest manifold vacuum) idle will tell us some things about what's going on inside (functionally, and orifice/passage cleanliness) and/or primary idle/transition calibration... and also whether the power valve/gasket is leaky. Report back, please. Otherwise, if after idle mixture is set lean-best, and idle speed is at where it's to be, grab two 3/8 wrenches and tighten (compress) the accelerator spring bolt/nut until there is some slop, some clearance at idle, and then loosen (expand) the spring bolt/nut just until there is no slop/clearance at idle. Let us know how you make out.
    Last edited by Walking-Tall; 01-30-2019 at 11:51 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  4. #4
    FEP Member mcavalear's Avatar
    Join Date
    Sep 2010
    Location
    Holly Springs NC
    Posts
    110

    Default

    Sorry it's an 80457 with the side hung floats without external adjusters. I followed a guide that said to use drill bits to measure their height by bending the tab that attaches the float to the needle assembly. I'll check the accelerator pump arm and see what happens.
    82 Capri T-Tops

  5. #5

    Default

    Well, if the drill bit settings landed the float tops roughly parallel with the bowl roofs, that should be okay, if those and the needles and seats are okay...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •