lyons Posted April 20, 2011 Share Posted April 20, 2011 81 hatch w/ea81, hitachi Hesitation off of idle...i've looked through the many posts on this...don't have the 200 to grab a weber yet.. It seems to hesitate most of the time - some times it will run for a few minutes without hesitation.. I've played with the two adjust screws, but am not sure what i'm playing with. There's a longer one that is off to the passenger side of the throttle chamber, and one right on the front of the chamber. Kind of at wits end with this issue..it runs, and idles fine, but as soon as you step on the gas it cuts out for a second or two, then it revs back up. While holding speed, it hesitates and lurches. No vacuum leaks, I've sprayed everywhere. What is the correct way to adjust the throttle mixture/idle? History is, I've swapped in another engine (blown bearings), with the old intake, seafoamed it, timed it to the FSM specs, replaced alternator, plugs and wires, cap and rotor, ignition coil and battery, ground to engine cable.. Quote Link to comment Share on other sites More sharing options...
Caboobaroo Posted April 20, 2011 Share Posted April 20, 2011 The adjustment thats on the base directly in the center is the idle mixture screw. The other is the idle adjustment. As far as tuning them, I cannot remember off the top of my head as its been a few years since I've dealt with a Subaru with a Hitachi. Quote Link to comment Share on other sites More sharing options...
ferox Posted April 23, 2011 Share Posted April 23, 2011 What is the correct way to adjust the throttle mixture/idle? History is, I've swapped in another engine (blown bearings), with the old intake, seafoamed it, timed it to the FSM specs, replaced alternator, plugs and wires, cap and rotor, ignition coil and battery, ground to engine cable.. Replace your fuel filter. Under car, in front of driver's rear wheel. Did you seafoam the carb or the engine or both? It is probably best not to mess with the adjustment screws until you know that the fuel circuits in the carb are cleaned. In fact it's a last resort. The car did not start driving the way it is because the mixture screws got out of adjusment, so if you mess with them you can easily end up confounding the diagnosis. Many a subie goes to the junkyard because people do that. I also drive an '81 hatch and lived in Durango for a while (6,500 ft) and there was only so much that could be done about the thinner air. This may be totally unrelated, but my '81 ran much better after I deleted the External Voltage Regulator. Don't go there until you make sure your entire fuel delivery system is clean though (filter). Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted April 25, 2011 Share Posted April 25, 2011 Accerator pump could be shot - passages partially clogged, incorrect timeing, poorly working vacuum advance, worn throttle shafts, etc. Many things can cause a lean condtion when transistioning from the idle circuit to the primary circuit. Probably best to check timing and advance operating - do a tune up with plugs and wires, and then rebuild the carb. GD Quote Link to comment Share on other sites More sharing options...
lyons Posted April 29, 2011 Author Share Posted April 29, 2011 Thanks for the advice - I'm on my way tomorrow to get the correct filter, they told me at the subaru shop i was supposed to have one in the engine bay...so i put one in there figuring the previous owner took it out. Now i see the one under the rear driver. I took off the one in the engine bay to see if it helped, but no change... Do you know if the 81 has just the under body fuel filter, or should it have one in the engine bay as well? Where should the timing be set? (I'm at about 7,500 ft.) I have timed it, to the FSM specs, but how much to compensate for altitude? Quote Link to comment Share on other sites More sharing options...
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