No wonder | Case 580 CK backhoe, unable to get the carb adjusted correctly

I have a Case 580 CK backhoe with the gas engine. I have been unable
to get the carb adjusted correctly. The carb is really simple,
especially considering the machine is 1970s vintage, only two
adjustments. So working on the throttle linkage the other day I
reached behind the carb to grab the linkage and discovered that the
butterfly shaft moves back and forth about .125"! No wonder I can't
adjust the carb. The other end of the buttery shaft does not have the
same motion, it fits the hole in the carb body properly. A new carb
costs anywhere from about $200.00 to about $400.00 so I will be taking
the carb off and effecting repairs. At the very least bushing up the
carb body. But if the butterfly shaft is also very worn it will get
bushed too. I'm thinking that it would be best, as long as the carb is
off, to bush both holes in the carb body with some sort of bearing
bronze I have on the stock rack. Then the carb will be fine for the
rest of my life.
Eric
Reply to
etpm
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When I got my SB lathe, one of the first jobs I did with it was to turn some bushings to bush the throttle butterfly shaft on my ancient (late '50s) lawn mower. I think the carb body was made from zinc slag, it was so soft.
I used some yellow brass rod from my scrap pile, drilling and boring it, turning the OD, and cutting it off. That was when I learned that a cutoff tool can really mess up a thin-walled tube.
Then I thought to check the diameters of brass tubing at a local model shop. Damn. I could have saved some trouble -- one of the sizes fit the shaft with less than 0.002" clearance. I cut that stuff by rolling it on a flat surface, rolling it back and forth a few times under the blade of a sharp pocket knife.
Oh well. Have lathe, will waste an hour or two making parts you can buy for a few cents. d8-)
Reply to
Ed Huntress
How do you plan to jig the shaft into the original position to position the carb body for boring?
Reply to
Jim Wilkins
I have a 530CK, probably the same carb, and it had the same problem. I had helpers waiting on me so I hacked a repair in minutes, using an o-ring and some washers if I remember right. It's been working well. I don't use it much but if I ever have the carb off again I'll make a better job of the repair with whatever I have laying around. No need to even consider buying a new carb.
Reply to
Straight Shooter
Good idea - if you put in 2 bushings you can ream them to fit the shaft. Just be DAMNED sure you properly stake the little prass screws that hold the butterfly to the shaft when you reassemle it.
I'd have never believed a brass screw could go through a cyl wall if I hadn't seen it with my own 2 eyes (1968 292 Chevy six cyl).
And it was ME who was blamed for leaving the screw loose - - - -
Reply to
Clare Snyder
It was a pretty common failure. All the dust on a construction site, mixed with the inevitable oil on a loader tractor, and it just ground the heck out of the casting. The shaft is unde rconstant pressure too, which doesn't help things
I worked on those critters for about 9 months a lifetime ago.
Reply to
Clare Snyder
I insisted that a former employee notdrive his car until he retieved the air cleaner wing nut he dropped into and through the carb.
Reply to
Gerry
SMART - but that's when you know something is missing and out of place. This screw found it's way out of the carb and through the cyl wall about 600 miles from home with a load of farm wagons behind - - - If something goes missing while an air intake is open, NOTHING turns over before the part is either found or the intake has been THOROUGHLY checked to be CERTAIN the missing part is not hiding there just waiting to do it's thing.
That said, who'd EVER think a 4 stroke deisel could put a set of 3XL cotton coveralls through the intake and out the exhaust without slowing down?????? Likely a good thing the coveralls had a zipper instead of a row of metal buttons!!! Goot thing there was a chunk of 2X6 within reach - - - -.
I imagine the turbocharger had something to do with getting it down to size to go through the valves.
Reply to
Clare Snyder
Back in my motorcycle wrenching days, we had some moments like that. Fortun ately, we were equipped for even the worst of cases which would involve rem oving the fuel tank & seat and hanging the bike upside down with a block & tackle and shaking the errant part loose. Sometimes some more disassembly w as required, but gravity can be a real friend.
Reply to
rangerssuck
was the 2x6 to choke off the intake or to beat in the head of the guy who left the coveralls in the wrong place?
Reply to
rangerssuck

To choke off the air after the coveralls failed dismally.
Reply to
Clare Snyder
I've heard of runaways, but thankfully have never seen one.
I'll bet that was an expensive complete overhaul.
Reply to
Larry Jaques
They saved the block, heads, crank, cam and I believe even the pistons and sleaves. It was in for Turbo work (bad seals) so the turbo was going for a rebuild anyway.
Not even sure if they had to replace all the bearings.
Another 2 seconds and it would have "grenaded" for sure.
Why the mechanic didn't have a plank in hand in the first place I don't know - he KNEW the turbo was bleeding oil and should have known it was runnaway risk. (They had to stall it out to kill it when it came in)
Reply to
Clare Snyder
Were fuel shutoff valves installed on all vehicles after that happened, I hope?
Reply to
Larry Jaques
That won't stop an engine running on oil leaking from the turbo.
Reply to
Jim Wilkins
Wouldn't do any good - it was running on engine oil. The fuel pump was totally shut down. No diesel fuel was getting to the injectors - it was just sucking engine oil through the turbo.
As for "on all vehicles" this was in a service shop that sewrviced the company's rental fleet of kloaders, dozers, backhoes, skid stears etc, as well as customer machines. IIRC this one was a trade-in or a machine the company had purchased used, to recondition and either rent out or sell.
We did a LOT of that - buying equipment that had been through a fire or a flood, or just left sitting unused for too long, anf tearing it down and completely rebuilding it.
Reply to
Clare Snyder
Have seen a tiny clipped end of a cotter key break a piston. Can only imagine what a wing nut would do.
BTW it is possible to change a piston in an 8 cylinder 64 Impala with out removing the engine. PITA and more trouble than it was worth...
Reply to
William Bagwell
Possible to do a COMPLETE rebuild in the chassis - including replacing main bearings. On an early one you can even change the rear main seal - WITHOUT REMOVING THE TRANSMISSION.
On the same vein, had a couple of young fellows pull into the service station lot back in about 1969 or 1970 with a '55 or '56 Pontiac 6 cyl that was knocking pretty bad. This was in Elmira Ontario, and they were heading for newfoundland. They asked to borrow some tools and dropped the oil pan, pulled the cap from the bad rod bearing, and after cutting a piece of leather from his belt and getting a radiator hose clamp, he clamped the leather atound the crank-pin, and jammed the piston to the top of the cyl. After bolting the pan back on and putting the old oil back in, it started and ran- quietly but with a pronounced miss.
We gat a thank-you note from him a week later from Come-By-Chance Nfld saying they made it home with no more problems.
Reply to
Clare Snyder
A guy I used to work with told me about a truck he bought that ran a little rough. He got out of the Navy somewhere close to the East Coast and bought an old truck from a farmer to drive back to California. He said that even though it had a rough idle it seemed OK on the highway test drive. And the price was right. When he got to his folk's house his dad and him determined that one cylinder wasn't firing. Pulling the head they found a round chunk of wood had been hammered into the cylinder. So they just put the head back on. Eric
Reply to
etpm
They can go runaway on engine oil? Amazing. What's the cetane rating of engine oil?
That makes it harder.
That can be quite profitable.
Reply to
Larry Jaques

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