racking barrels gone bad

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oil_burner

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Jan 5, 2012
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So after a few frosty beverages, i got talked into racking the barrels on my pump. the whole 10 minutes it took to do went fine untill start up time. it started right up and idled around 900 thought all was good then blipped the throttle and it hung up around 15-1600 rpm. shut it down and checked linkages to find everything good. pulled the lines off and loosened the retainers up, felt a weird pop on a couple as i loosened them. moved them back and forth a few times with the dv socket and torqued them to 18 ft. lbs (searched but couldnt find torque specs) started it up and it took off to about 2500 instantly and i couldnt shut it down. intake horn was still off so i tried killing it with rags, with no luck so i left them on there and popped the clutch in 5th gear 4wd and killed it. tried tightening them down some more with the same results. from what i can tell by reading is a plunger is sticking, causing the rack to stick. what caused this to happen and whats it take to fix? if i cant figure it out by mid day tomorrow im pulling the pump and taking it to CDS i guess
 
Sound like you lost a shim from under the barrels. Time to send the pump out.
 
The shims will fall out, if you lost one pull the one from the other side and take it to a pump shop to get the same thickness. I lost one a couple weeks after doing it. When I tightened the barrel down without it it wouldn't start. Put a shim in and fixed it. Hope this helps, hope you didn't stick the rack. I've had that happen also, blew the engine up.
 
Don't ever use rags to kill an engine. Use a book, or clipboard, or anything that isn't going to get sucked in. Hopefully a pump is all you need rebuilt. If any of those rags made it to the combustion chamber you'll be rebuilding it. I've seen people leave rags in the intake after a rebuild and get stuck around the top ring, break rings, scuff cylinder walls, ruin a lot of stuff. Hopefully none got away.
 
tried a 2x4 first, was still sucking enough air to run. then grabbed a piece of 1x6, it was a little to long and hitting the injector lines. so i grabbed a rag and it slowed it down the most. you use whats available when your motor is screaming at 3500 rpm i guess.

Gwhammy- are these shims directly under the barrel? could i pull a barrel and be able to visualy see them?
 
chances are your barrels had a normal wear spot, and "racking" them pushed the plungers past that wear spot and forced them to stick the rack.
 
yea with 260k that makes sense. i just fooled with it some more, loosened all the barrels and rack moves freely. Started tightening them one by one and checking the rack on after each one. it moves free untill i torque #6, its also the one im getting a slight pop from when i tighten it and loosen it. would loosing the shim under the barrel cause this? im thinking about pulling the barrel and taking a look around
 
Check the shims under that barrel, they maynot be matching dimentions
 
The shims are easily seen from the top of the pump they are under the retainer with the two bolts you loosened to turn the barrels. One on each side...

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yea I figured thats what he was talking about. they are all there and in the same location they have always been. I will go out and measure them soon. I did pull the #6 barrel out and everything looked good, reinstalled and with all the barrels tight the rack was still free. put lines back on and it fired up and idled ok but its still sticking and hanging up when you touch the throttle. I really dont have the spare money to send it to a pump shop right now and i feel like its just some goofy little thing making it hang but im about fed up with it at this point
 
ahale2772 said:
chances are your barrels had a normal wear spot, and "racking" them pushed the plungers past that wear spot and forced them to stick the rack.
Click to expand...

This ^^

Not to make you sound stupid at all but, have you tried moving them all back close to the original spot?
 
yea looked clean as can be, and the shims are within .005" of each other. it almost i can move everything back but not forward. it almost seems like its "defaulting" back to about 1/4 throttle. so i can push the rack backwards towards the cab about 1/4" then it stops and i can push it that little bit left for shutdown.
 
I've heard this story often.
The good news is you can now get your barrels balanced and cranked at the pump shop while it's there getting fixed.
 
Snedge said:
I've heard this story often.
The good news is you can now get your barrels balanced and cranked at the pump shop while it's there getting fixed.
Click to expand...

This is Jeff's nice way of saying... Wow! You really Fukked up! LOL
 
So why would the rack start resetting itself to ~1/4 throttle and move back all the way, a hair forward but not all the way forward and not return to to correct idle position? Most of you guys probably have more knowledge of the internal workings of these pumps so why not shed a little light on what could be going on other then just saying send it out because your a dumbas$? I'm not at all against having it benched at a shop, I just want to learn more about them in the process...
 
This is from what I have seen myself in the few I have dug into, but without seeing it this is my educated guess at what is going on in your pump.

The pumps over time will develop wear areas on the internal parts (ie: plungers, barrels, DV, rack assembly) that they normally operate in. The rack travels in a reciprocating motion. When you attempted to rack the barrels opening up the spill port for more fueling you moved it out of this area it has been in for 260k (if nothing has been tampered with before) by doing that you possibly created a bind somewhere that the linkage from the governor and throttle linkages can't overcome to actuate the rack correctly. People figure your just slightly tapping on each one what "you" think is an even amount to rack them but in reality is not and things like this happen. Again this is just my opinion of what most likely happened.

Here is a view of the internals.

click


click
 
are you attempting to move the rack with the shut off solinoid still on? afc on?
 
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