Fulcrum lever observation

[RCCUMMINS89]

So yesterday I took my pump off to do a few things......... I was observing the fulcrum lever through it's motion from the fuel screw as well as the throttle part of it.

I noticed that the throttle itself would move the slide collar the correct way for about 3/4 off it's sweep and then hang out in one spot and then move the wrong way (towards the defuel direction) for the last little bit.

So those who are getting full throttle travel may actually be defueling the last little bit of throttle.

I noticed this on my truck about a year ago and never knew why, I now know that don't just take out the high idle screw and throw it away.......it like the rest of the pump has it's purpose and needs to be adjusted accordingly.

[BC847]

I observed similar defueling with moving the throttle linkage to the inner hole on the throttle lever of the IP.

[skilletky]

great info! i noticed this on mine also. mainly when i switched to the 4200 spring. time to tear the garage apart and find my idle screws.

[Mark Nixon]

Just another little tidbit that some people never knew. I know I didn't.
It sure seems like manufacturers LOVE to sneak in little tricks to throw us off, doesn't it?

Mark.

[RCCUMMINS89]

What I noticed was that at full throttle I'd notice my boost would flutter............. If I let off the tiniest and I do mean tiniest bit it would quit. I'm now under the assumption that the slide collar probably bounces a little bit when it's in that heading in the wrong direction mode.

[PToombs]

How were you seeing the lever? With the top off the throttle isn't hooked up.

[RCCUMMINS89]

Yes, but I can move the lever by my hand..............

When i had the throttle rod and gov spring hooked up, I pretended to put it in the proper spot.

The slide collar would move the correct way for well under 90 degrees of throttle movement. So, if one is getting that much movement they are losing fuel.............that is of course if that pump is like mine.

[Sutter1stgen]

So without taking the pump off, the best way for one to know if they're pulling too far, is fluttering of boost. I'll have to pay attention to that next time.

[BC847]

I let off at 4K . . .

[RCCUMMINS89]

So without taking the pump off, the best way for one to know if they're pulling too far, is fluttering of boost. I'll have to pay attention to that next time.

? Not sure if all would act the same............

[D-dog357]

That explains a lot. After swapping holes, taking out the slack, grinding the throttle lever and adjusting the high idle screw out till the lever is just short of rubbing the cold start tube. My truck seems to fall on it's face when I stomp on it at a light. 3/4 peddle seems to pull harder then full. Not that my toad pulls hard to begin with.

Time to re-adjust the high idle screw.