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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: brianzero on October 02, 2022, 12:14:57 PM

Title: Rack Disconnected from Throttle Lever?
Post by: brianzero on October 02, 2022, 12:14:57 PM
Hi All,

In the continuing saga of my no-start situation, I decided to pull the valve covers on my heads to see if my injectors were frozen up. I cleaned out the injectors and verified that they do move freely. The rack moves in what seems like fairly free as well.

Here's the strange thing; I noticed that my throttle handle does not move the rack. I move the throttle handle back and forth, and it does nothing. The fuel shut off lever does move the rack. Whats happening here, can anyone explain? Is the throttle linkage broken?
Title: Re: Rack Disconnected from Throttle Lever?
Post by: Nova Eona on October 02, 2022, 04:25:04 PM
I may be entirely wrong in this because I'm most familiar with 71 series and far from an expert there, but I believe that's to be expected because the throttle lever is only meant to actually control rack position between minimum and maximum governed RPM - above and below that range, the governor has full control over rack movement.  With the engine off - below minimum RPM - the throttle lever shouldn't have an effect on rack position.

Someone more knowledgeable please do correct me if I'm wrong here.

Also, I think this video is the gold standard for explaining the governor and linkage - specifically for 71 series again, but I believe the 92 operates similarly.
https://www.youtube.com/watch?v=z-jjTaZlu28 (https://www.youtube.com/watch?v=z-jjTaZlu28)
Title: Re: Rack Disconnected from Throttle Lever?
Post by: brianzero on October 02, 2022, 06:38:03 PM
Thanks Nova. I had no idea that linkage and governor system was so complicated!
Title: Re: Rack Disconnected from Throttle Lever?
Post by: luvrbus on October 04, 2022, 03:40:40 PM
They are not a true governor all they do is limit the low speed and high speed RPMs,the buffer screw is the place with you can screw up ,you should see a slight movement in the linkage when moving the throttle with the engine shut down off and you should be able to move the linkage from no fuel to full fuel with no effort if not, I wouldn't fire it off