fast idle disable throttle?

[bevans6]

I thought fast idle on was supposed to disable the engine speed control, so that it was over-ridden and you shouldn't have any reaction from the throttle pedal.  I was just moving my bus, and happened to goose the throttle pedal while fast idle was on, and the engine reved up high, to governed speed I think, for a second or two before it came back down.  what's up with that?  8V-71 mechanical, jake brakes and jake high idle switch.  Jakes were off.

Thanks Brian

[wildbob24]

Brian,

Sounds like someone has either removed or disconnected the air cylinder that stops the throttle lever when the fast idle is engaged . There should be 2 cylinders an top of your governor: One is the engine stop and one is the throttle stop.

They are each controlled by a Skinner valve, so the problem could be there, as well.

Bob

[luvrbus]

Brian, that was caused from fuel build up from idling if it went back to normal in a few seconds



good luck

[bevans6]

Problem solved.  On my bus the air line comes from the Skinner valve to the throttle stop air cylinder, tee'd off to the buffer switch cylinder for the high idle.  Everything was working fine but - the engine speed lever was positioned too high on it's shaft, the push-rod from the throttle stop air cylinder slid under the little tab on the lever it was supposed to hit, and instead kind of hung up under it.  I repositioned the engine speed lever lower on it's shaft and all is fine.  I also checked to see if it had full travel at full throttle, and it does, so all is well.

Brian