Setting a Bosch idle

[Flynn]

Right, trying to get this thing idling right. Everytime I start it up it seems to have a different idle. I am adjusting the throttle rest screw (at the back of the pump), the max fuel screw and the throttle arm on the splines. On the current settings I have got it to idle at ~1k but a couple of times it has played up and tried to "run away" when I have pressed the throttle arm, so I want to change the settings because I don't want it to do that when driving. I am running a governor mod, that's all, the distrub. head hasn't been removed so it's all fine internally. Something to note, the throttle travel currently stops before the throttle lever reaches the body of the pump, could this be causing an erratic throttle response? And when it tried to run away I pressed the stop lever which returned it to idle but only stopped it if I pressed and held it, I don't know whether this is normal or not. The idle is a clattery idle though, not a normal one. Once when I had adjusted it to a steady idle and pressed the throttle it revved normally but returned to a clattery idle, I don't know why it did this as the throttle rest screw was still in the same place.

[the man 53]

How did you do the gov mod?

[Flynn]

With a nut and a washer on the governor spring shaft. It was still compressable.

[bscutt]

Are you sure you don't ave any throttle shaft play? That in conjunction with the mods could be contributing to the lack of a repeatable idle setting. Just a guess on my part - I had a pump with throttle shaft play that would change idle speed especially when the pump got heated up completely.

[the man 53]

which spring on the shaft? If you did the wrong one you will have these issues.

[Flynn]

Are you sure you don't ave any throttle shaft play? That in conjunction with the mods could be contributing to the lack of a repeatable idle setting. Just a guess on my part - I had a pump with throttle shaft play that would change idle speed especially when the pump got heated up completely.

I don't think it has any sideways play. Although all of the shaft and cradle assemblies I have handled seem to be very loose and have up and down play, but that wouldn't affect it. I have tried it with a couple of different assemblies when I was having the same issue on my old pump but that didn't seem to help.

which spring on the shaft? If you did the wrong one you will have these issues.

It's this one:

[the man 53]

If that is yours I would assume that the OD of the washer is too big and rubbing the cage. You did shim the correct spring. See if you could find a smaller OD washer or replace that washer with another nut. The way that cage around the springs are it is a touchy area.