Boggy / Funky engine response?

[Edelbrock]

So it s a 2005 Joyner 800 CC (3 cylinder). 

 

  Starts and idles great. 

  Sitting in neutral, it revs up nice as long and you dont stomp the throttle too quickly, then it will sputter as it climbs RPMs but cleans up and fires on all 3. 

  Starting off in first, you have to get the RPMS up pretty high and then slowly let the clutch out. If you release the clutch too quickly, it BLAH and loses RPMS and dies, almost like it has no flywheel wight at all. Sp you kinda have to ride the clutch a bit to get her going, ESPECIALLY uphill. 

   Once up to speed, it does fine and sounds good. But if you are in the lower RPM range and lower speeds (1st) or (2nd) gear, you have to slowly accelerate. If you stop the throttle, its like someone turned the key off - it just stops firing on all cylinders instantly, then begins to accelerate, then the cylinders kick back in and it takes off pretty good. 

    Stomping the gas makes the accelerator pump spray pretty good, and applying the choke doesn't help - so I don't think its running lean at WOT.

     Almost seems like a timing problem or something, like of the timing was WAY off.

    What I tried: 

     Random timing settings, by hand.

     Adjusting the timing to spec. 

     Replaced carb

     Blocked off vacuum advance, then switch back to OEM. 

     Checked plugs. 

     Fresh fuel. 

     New fuel filter. 

     Checked air filter. 

     Checked charging system. 

     Checked for / fixed vacuum leaks. 

     Checked distributor cap and rotor. 

   

     Should I try adjusting the air screw on the carb??

    I would be open to any ideas. 

 

   Thanks. 

 

 

[Joe Breaux]

The A/F screw only affect idle and low rpm mix..sounds like timing is not advancing with increasing rpm..but thats just a guess based on car engines acting that way

[Edelbrock]

Thanks for the info. 

I will try using an ignition bypass box today to see if that helps.