engine slow to decelerate, or un-rev

[Josh]

I'm not sure how to articulate this; here's what's going on.  I swapped an injection pump; it's a temporary swap whilst I replace a few seals, etc.  

  Anyway, this pump performs well; the mileage I get is on par with the 48+ mpg I'm used to in the quantum.  

  The new and different behavior is that the engine's RPMs do not quickly drop when revving the engine.   It takes a few seconds for the RPMs to return to idle level.  

  My guess is that this pump has had an extreme gov'nor mod done to it, but to those of you who've screwed with other fueling changes, have you ever encountered this symptom when adjusting fueling screws, etc?  

  I'm going to measure the positions of the fueling screws on other quantum pumps known to be good, and compare.  But in the mean time, I thought I'd ask.  

  Thanks,
   -Josh

[bryanbryan89x]

I am definitly no expert on this, but when I did the Gov-mod, my rpms would drop real slowly, I did a counter clockwise 1/4 turn on the max fuel screw and it was fine.  Also if you decrease the idle screw it drops rpms quicker as well.

[hillfolk'r]

yea the last post was right,,,,if idle is too high,,or max fuel turnerd in too far,,itll do this,,,,,turn max fuel out a little,or idle speed lower a little,,,,,idid the int. spring mod,,mine would dothis too,,,and i couldnt get it right,,so i removed the shim,,,,,if you go too far to lower idle,i had a wierd thing happen,,if iredlined it,pushed clutch in,and as it dropped to idle,it would stall out,and restart  was very hard,,i would have to crack hi psi lines loose tilligot fuel,,,,strange,,,,,totally opposite,of hanging revs,,,,,,try dropping the idle toaround 850-900,,,itllbe ok,,,,,,,,