Runaway...why?

[ahale2772]

Looking to find an answer for why a VE will actually go to runaway.... and at the same point dispel some rumors about what you can do IF a pump starts to runaway. I tuned a 4bt a few weeks ago and at 3 screws the pump wanted to keep going if you revved it in neutral... very scary, and doesn't give the customer a good feeling when I tell them that my truck tries to do that as well...

1) what causes the pump to actually run away on itself? what can cause it? I want to know excactly what lever is pushing what button to cause a pump to run away... not just "anything over 3 screws and your in danger"

2) is there any way to see a symptom of a pump that will run away? ....instead of just "blipping" the throttle and just seeing if she goes... case pressure rise? drop?

3) say one goes to far... and the pump runs away, why would the electric shutoff not work? just because it dosnt have the balls to shut off the fuel to the plunger under high flow? how about the manual shutdown lever? why will that not kill one that is running away?

this is a no-rumor zone, if its something that "they" said, keep it to your self. the 1stgen community needs answers!!!

discuss....

[BC847]

Understand that at the end of the day, all the fuel control mechanism does is locate the collar covering the spill-port as the piston moves in, out, and around the head.

- Setting the fuel control mechanism such that the spill-port is constantly, effectively covered to the point the engine gets enough fuel so as to be just above that required to maintain it's current speed will result in Run-Away.

I'm soon gonna do a thread on how all that stuff works (with pics).