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William, are you sure it isn't sloped in this area?

227669.jpg
 
William-

I hate to say it but that crank needs replacing. It appears from the first photo that some of the shaft itself is worn and it's probably out of round. I doubt you will be able to fit a basket pulley on there well enough (snug). If you were to install the pulley on this shaft I'd bet its life span would be a short one compared to a proper fix. You don't want to have this problem again a year or two from now. I don't think a machine shop could even bring this crank back to standards but Ken or Dennis (or someone) might know differently.

Of course, this is just my opinion...good luck!
 
Wayne, I thought that when I first saw the photo but I believe it may be an optical illusion due to the bright back lighting.
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There is no doubt it's in bad shape, but I'm not so sure it's worn out of round, too badly...
 
William, I have had cranks fixed by cutting anouther keyway, cheapest fix, 180 degrees out from that keyway. That means best case, that crank still has to come out. Have you checked locally or here for good used crank?
 
William, WAYNE - The crank in my K321 had been BRAZED in that keyway to make the basket pulley drive key snug in the groove again, and the engine had an OEM sized piston, had never been rebuilt, so it wore fast. Wyatt gave me a good crankshaft so I didn't have to reuse the worn crank. The larger HP engines when pulled to their potential do that kind of wear, they only put power or torque to the loads on either end of the engine for about 45 to 60 degrees every 720 degrees of rotation, it's NOT a smooth flow of power in spite of the heavy flywheel. Keepng the set screws tight so there's as little movement as possible helps, and yes, mowing tall grass, pulling the engine hard all contribute to that type of wear.

I think the keyway is either 3/16", or 1/4 inch square. Best thing to do is buy keystock in 12 inch lengths and make your own keys as long as you can to distribute the force over as long a length of the crankshaft as possible. The K-series cranks were cast gray iron, not really able to be welded real well, You could but you'd never be able to remachine the keyway properly, some people machine another new keyway 90 or 180 degrees from the worn one. The K-series crank I understand is NLA but the Magnum series crankshaft is available and is cast Ductile iron which is quite a bit stronger and I've read here it's a direct drop in part, no modifications reqauired if you get the right spec number crankshaft.

Also, it's just about Impossible to machine inside sharp corners in ANYTHING, so the pic Kraig posted the circled area is radiused from the tapered portion of the crank to where all the wear starts. Heaviliy stressed parts HATE sharp corners and abrupt changes in cross section and that would be one heck of a good stress riser which would allow the stub end of the crank to break off. I've seen that happen even on nicely radiused keyways or splines.
 
Well, I took a good look at it, rotated the engine, used a straight edge, etc.

The shaft itself, it still round. It may be worn down in a few spots, but it's still relatively round. The keyed part is sloped at the very back, like the first "wear" picture, but I meant as far as the "extra" wear area. The one pictured is like a "gentle curve" where mine is rather abruptly cut off.


Looking at my picture, the area between the green lines look fine. Still the same diameter (or extremely, extremely close) as the rest of the shaft. However, the area between the red lines are worn. They are worn evenly, and that area is narrower than the rest of the shaft. MY guess, is because of the V-belt pulling on it. That doesn't add up, exactly, because if the shaft is spinning, the entire shaft should be worn down fairly evenly, not just that one side.

http://i283.photobucket.com/albums/kk282/1994LTCSS/Shacft.png


I'm not "scared" of replacing the crankshaft, but I've never torn down a small engine completely, and I don't have any special tools that would likely be needed to rebuild/overhaul the engine. I don't plan on cutting grass with it, so the only purpose the pulley needs to serve is for the starter to function to start the engine, and for the generator to charge the battery. If I decide to restore it, a rebuild will be pretty much required, but until then..
 
JB Weld??
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Don't forget that the crank's rod journal will almost certainly need to be reground also (more$$). My experience with a similar situation says that unless the fit between the pulley hub and the shaft is close to original (I'm guessing a .001" or so) you just can't keep things tight - it'll loosen up and start chewing things up again. That "big bang" power impulse every second revolution is absorbed by both the flywheel AND that big starter pulley. If it wasn't undercut, a second groove and a clean pulley bore would probably work..

(Almost OT warning) - A top fuel crank shaft twists so much from front end to back (at high RPM) that a lot of tuners actually have cams created with a front to back twist to compensate ..

Edit.. If you could find a shop that had an old Stoody powder spray torch and the right powder for cast iron buildup (IIRC it's nickle powder), you could get the nose built up and then ground to size. It's one of those jobs that you might get done on a "when you have time" basis to cut the cost. Some of these areas are dealt with all of the time by the guys with the big antique gas engines... (check the Smokstak web site).
 
Gerry, you trying to wake up KENtucky with that JB Weld comment?
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William - Gerry gives good advice on the metal spray welding, several companies I've worked for approved it for even brand new OEM parts.

Since you say you don't need the PTO since you don't plan to ever mow, you COULD get a "Taper-Loc" pulley about the same size as the S/G pulley. That style pulley uses a mounting bushing tapered on the OD and the pulley uses a matching taper on the ID and as you tighten the bushing into the pulley the bushing very tightly clamps down on the shaft. Those style pulleys are quite a bit more expensive than the stamped steel OEM pulley, they're all cast iron, but they can be installed on your existing shaft, with just the elongated key. The only torque you need to transmit is for starting, once the engine is running the generator only pulls a fraction of a horse power, lets see, 15A x 12-14V = roughly 200W & 746 W = 1 HP, so .268 HP. I think that would be your cheapest best quick fix that should run for a long long time. Been a while since I bought a taper-loc pulley, but I know they should be cheaper than the gasket kit to install a new crankshaft!
 
I guess out of round may not be the best wording for this cranks condition even though it's possible. Like Gerry said, unless the fit between the pulley hub and the shaft is close to original you just can't keep things tight. That, along with a heavily damaged keyway would make me start looking for another shaft. It'll require a little more attention now but will give you the good, reliable trouble free service we all expect from these kohlers.
 
Dennis:
I'm using that style pulley/hub on my Vanguard powered Cushman Eagle. It will handle the horsepower (I've seen them on 22HP versions, at least in the solid sheave style). The problem is the "squeeze" probably wouldn't be enough to clamp to the undercut shaft AND it would still require a key. I know that the OD of the pulley needed (ummm 10" maybe?) would probably call for a spoked sheave rather than a solid one (I think the one I used is about 5.5" and weighs about 5 pounds!)

Holy crap -stop the press!! I just priced a 10" on WW Grainger's site - buy another crank... (and Grainger needs a database/web interface programmer - I spec'd single groove, bushed sheaves and it gives me about 80% double groove, bored to size ones).
 
Gerry, it could be worse, ever go to Tractor Supply site. Poke in an item in its search box and you get a 25% chance that it finds what you asked for !
 
thanks for the manual on how to remove the engine, it worked with no problems. But.....I am having the worst possible time getting those screws off the fender footrests. I sawed down more to make a grove for the screwdriver, went alright. I heated it with a torch, removed 2 screws and the rest, not coming out as planned.
 
Brandon-

You almost HAVE to have an impact driver. This was discussed here recently...a few days back. I use an impact driver to remove and install these bolts. Soaking them a little in PB doesn't hurt either.

Good luck.
 
Brandon:
I stole this picture back from cubfaq #94..

227675.jpg


Note that I hadn't cleaned the slots before taking the picture.. Also, If you've boogered the slot up, a Dremel tool with a thin cutoff blade works pretty well for cleaning up the walls of the slot (it'll be wider, but you can get pretty sharp corners, just run it in the slot like you were cutting a new one..)

Wayne - I woulda been there first, but it started w/lightning storm , I decided to take laptop out of lap (AND I just had a BIG hit close by while typing ....)
 
Hi all, thank you for the advice. I think I'm going to go the only route one really should, and that is to find a used crank/pulley, and when I rebuild the motor, replace them. Any idea of a ballpark figure as to what that would run me?

Now, that being said. I went to put it all back together this evening, and I figured, "eh, why not?"

I slid the pulley on the crank, except, this time, I rotated it so both of the hex bolts will be turned so they will screw directly on the crank itself, instead of in the key/notch like it's supposed to.

Hey, it worked! Quite snug too. Smacked the outer edges (lightly) with a ball hammer, and it didn't budge. Ran it for about 15 minutes, and it's just as tight as it was before. Not a permanent fix, but it'll do for now. When it slips eventually, I'll just rotate it again, and go from there.
 
GERRY - My first stop while looking for one of those pulleys would be my local Blain's Farm & Fleet, they have a pretty fair selection of bushings & pulleys. Next would be the Motion Industries store across the Boulevard. If they're ten inch, I'd like to think you could get bushing & pulley for $50-$60.

And yes, I mentioned in my last post to still run the longest key you could. I think they bushing would tighten up on the shaft if it's only slightly worn as William says. The spoked version would be fine. I've actually had two of the basket pulleys spin on the crimped-on hub and had to tack weld them. Even my 7-1/2 HP compressor motor has that type pulley on the motor. I've seen them on really large implement drive too. Your only limited by the belt/belts you run.
 
William:
Not sure how far it is from Surrey to Culpepper, but you might just want to take a minute and go peruse the Classifieds For Sale back around the 11th. Kevin R. had a couple of cores listed..

edit:
139 miles per Mapquest, not a bad trip for Cub parts..
 
Man, I gotta go find the RightGuard.....
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<font size="-2">Say -is that really Homer Simpson? sure looks like him..</font>
 
KENtuckyKEN. Sorry about that wrong name. The heat must be getting to me. It was just terrible yesterday when I got off work and doesn't appear to improve until the end of the week. I am having another cup of coffee though.

Just can't find those broken hydro pics anywhere.
 

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