weird rpm drop after touch throttle

[91bluecummins]

i have a 93 w250 6bt that im working on and a 4bt that does the same thing and it has a weird drop of rpms when you let off the throttle. When it gets to idel after you let of it acts like it misses for just a second. Then rpms go back up and runs regular. i have no problems any where else, no fuel leaks. Its like the pump cuts out for a second after you let out of it right before you shift or when you just revving it. What could cause this pump pressure, fuel pressure, idk. ill post a video later.

thanks

[fatty]

Mine does that too. Always has as far as I can recall. I just figured it's the nature of the beast under the hood.

[RCCUMMINS89]

Mine does that if I'm on the very verge of runaway... the governor isn't operating smoothly at that point, due to the angle on the fulcrum lever........at least that's how I see it in my head.

[91bluecummins]

well it could be that but it did it before i turned it up. would a very small fuel leak do that, its at the fuel pump though.

[Remps]

Is the throttle linkage sitting right on the idle screw at an idle? No gap?

[cougar]

Does it do it if you slowly let off the throttle?

[CumminsPower59]

I've had the same issue, but only with the 114 pump that Iam currently running. The more the fuel screw is in, the worse off it is. The 184 and 205 pumps that I have run haven't had that specific issue. Before I went through the 114 pump, it leaked something fierce, but it didn't have that idle drop either. Kind of annoying to be honest, but I have turned the pump down a bit and it isn't as noticeable. I have tow core 114 pumps I am going to build, so hopefully the issue will be with just the one pump.

[RCCUMMINS89]

I've had the same issue, but only with the 114 pump that Iam currently running. The more the fuel screw is in, the worse off it is.

Mine does that if I'm on the very verge of runaway... the governor isn't operating smoothly at that point, due to the angle on the fulcrum lever........at least that's how I see it in my head.

[91bluecummins]

theres no gap in the throttle, and it did it before i turned the pump up, and it was stock