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John Deere 50V Repair Tips

Jeff Schmitz

Jeff Schmitz

New Member
Joined
Oct 10, 2017
Messages
1
Location
Alaska
I have an old 1990s John Deer 50V made by Kioritz in Japan. We've had it since new at a family cabin in Alaska. Relatively heavy but runs fine and has a lot of nice touches - adjustable auto oiling with manual supplement, adjustable idle knob, trigger fast idle are the biggies. I did three repairs recently, kicked off by the first. In cleaning out sawdust, etc from the clutch area I discovered that the forward bar stud was stripped. The clue was when backing off the lock nut the whole stud turned out! Cleaning the area showed up curly metal, threads from inside the block. Looked like it had never been properly seated at the factory. Rear stud OK. they are Metric, 8mm x 1.25 thread pitch. Once I got to looking deeper into the stud pocked I could see unused threads further in but the factory studs were half an inch short of picking them up. Ultimate solution so far, time will tell if durable was this. Drilled out the pocket to ~5/16, be careful not to go through the casting into the crankcase! Use the good pocket as a depth gauge. I ran a 3/8 x 16 tap down the hole for grip purposes of the JB Weld (long cure, not fast) I used to epoxy a new stud in. Elected to stay with metric, no reason a 5/16 X 18 or so SAE could not be used but both studs would have to be converted. Cleaned out the drilled pocket with brake cleaner to degrease/dechip it. I had ~ a 150 mm piece of 8x1.25 allthread, cut it into a pair of ~50 mm total length studs. The cut ends go in the pocket, the "clean" ends are on the outside for easy nut installation. Seated the "good" pocket replacement stud using twoblocked nuts being careful not to over torque it into the case. Mixed the JB weld and lightly coated the "threads" of the injured pocket and the replacement stud and seated to depth. Make a trial dry run and mark the stud with a felt tip at flush level to make sure JB weld is not filling the very bottom of the pocket. Allow to set for at least 25 hours, I set mine for over 30 while I worked the other problems. Now. There is considerable slop in the bar slot even with the original studs, the all-thread doesn't help this. If you can lay your hands on decent length studs it might be a better way to go but still doesn't really address the slop problem Most saws are this way but in this case it aggravated the existing weakness by requiring a LOT of torque to lock the blade at the proper tension setting and the front stud takes the worst of the beating. Hence the failure here. So far a success, it takes good torque although I have not put the Magilla on it! As a bonus I I had the rubble from a Stihl 024 which uses the same 8x1.25 thread but a much larger nut size that happens to be - wait for it....the same as the Plug for the JD! One scrench now fits both the plug AND the bar nuts! Bonus! And I can put the original JD nut (13 mm/1/2 inch wrench) in my field kit and have spares if I lose one or both Stihl nuts. An alternate fix would be to Helicoil the studs, both SAE or Metric would probably work, there looks to be enough "meat" in the bosses to tolerate this. Spendy fix, Helicoil kits are not cheap and a tap is needed. I would use a "bottoming" tap for this as max thread engagement is crucial.
Next up was to fix the kill switch that had been inop for shutting the saw off but allowed it to run. The switch is a nasty piece of work in all respects - hard to operate and even harder to fix as it is part of the top cover that also holds all the Rube Goldberg mess/pivot for the throttle, interlocks and the manual oiler! Turned out the problem was a combo of corrosion on the cover (magnesium) and parts of the switch metal but you have to take the cover off, etc. The cover is used as a conductor to a strap to the block.... I would not do that again, I considered myself incredibly lucky to get the linkages and pivots back into the same formation with the cover and carb. There is plenty of room for a toggle switch in the front of the cover and will have that as a backup if the same problem comes up.
In troubleshooting the kill switch I had to take the fan/recoil starter cover off and found the fuel line had literally turned to foamy mush! This apparently is a very specific line made for the JD/Echo machines - it has to have a large size at the fuel tank end, necks down to much smaller to fit a slot in the fan case then has a combo dust plug/upsize section molded onto the carb end which is a different size than the fuel tank! Sheesh. Solution was vinyl fuel line, a short ~ one inch "stub" for the fuel tank end and inserted a smaller size well into it that "fit" both the fan case slot and the hole in the carb box/carb fuel port. The fan case comes off easy but can be a bugger to get back on, the pawls for the recoil are not your friend! Four things all have to line up - the case screw holes, the pawls have to open up for the recoil shaft, the fan case has to slot into the rubber carb adjustment cover and the choke linkage has to mate into BOTH holes in the choke plate! The pawls will sometimes open with a slight pull on the starter rope but the other path is to take the screen off the fan case and push the pawls out of the way. While doing the other three things of course! The saw was really easy to flood now with a fuel line that was up sized, not leaking or collapsing!
So now the saw is much happier and it got both the chains I have in town sharpened in the bargain.
FWIW the saw is a 16", 3/8 pitch, .050 gunge with 60 drive links. Oregon bar and chain, 72 Oregon series chain that as best I can tell is a semi professional type using a 7/32 file size and 25 degree sharpening angle vs 30 degrees. The "25" stamped on the raker teeth means .025" for the proper cutter/raker depth difference, the raker being filed lower as the cutter is sharpened over time. I have three chains for it and may pick up another as the saw lives at a remote cabin. Oregon does make a combo bar/chain kit (Oregon® 27851 Bar & Chain Xtender, 16" – toolboxsupply.com) for it as well, that may also the source for another chain. Recently saw a piece that described freeing a stuck saw by releasing the power head from the stuck bar/chain and installing a spare bar/chain to free the stuck one! What's not to love!
Hope this helps the JD/Echo community, this site is gem!
 
Coopacres

Coopacres

New Member
Joined
Jan 20, 2020
Messages
1
Location
Canada
Hello I've recently obtained a John deere 50v like you mentioned in a prior post.( echo cs452vl ) I hoping you can help me with a recoil spring question. Unfortantly the recoil spring assembly is apart but not broken , I'm not sure how to reassemble as there's a ring as well as the recoil spring . ( the ring is the same width and material as the recoil spring , it fits into the housing but I dont understand how the spring works with this ring? Any light you could shed would be greatly appreciated. Thanks very much.
 
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