I have a 1979 610 bobcat. The fellow that use to own it, told me to never use the lever for high speed. I took his advice, never really thought much about it. At that time the thing just barely ran good enough to pull itself around the yard, So I never really investigated it. Recently I rebuilt the carb and put new gaskets on the manifold, so it will actually run without having to choke it all the time. Temptation got the best of me last week so I pressed on the handle and instantly the big drive pulley popped off. Was a bit of a struggle to get it back in place. Any Idea why this is happening?
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We have a 1975 m-371, and it has two pulleys on each end of the belt, and only works right if it's on the inside two. I'm not really much of a mechanic, but I'd see if you have the belt on the right pulleys. It could also be your belt's worn or your pulleys maybe aren't straight? Good luck!
Your big pulley popped off? You're saying the driven sheaves seperated, or the whole assembly just slid off the shaft? The only pulley I have seen come off is the drive assembly. but it's always tricky to work down deep in the loader like that. I like the high speed, it lets the Bobcat go 7 miles an hour, and it's the right seting to show off with wheelies for friends...LOL!
The entire pulley assembly comes off of the shaft. The large pulley that mounts on the tapered shaft of the engine.
The taper on the engine should hold it in place. There should be a bolt and washer to hold it on the end of the shaft so it will not be able to simply slide off...... I don't know this machine, but every taper and pully setup i have seen uses a bolt to hold pressure on the taper so it will not simply let go.
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Pretty sure that should never happen weather you use high or not. Look for a broken or missing bolt. Something must hold the sheeve on there. It can't just simply be wedged on the taper.
I can't understand why it does not happen in lo????
Ken
If memory serves me correctly. The pulley assy. on the engine is hydraulicly controled. I have seen the cylinder assy. on the engine come apart. But to be honest I'm lucky to see maybe 3 or 4 of the ole 600's machines. Considering the age of the 610 I could see it coming apart especially if it hasn't been used in a long time.( rust, corrosion..etc ). I'd bet that the speed lever hasn't been moved while running in ages. At least thats what I gather from what you say about the previous owner.
Wow! is there no way to edit a post?
Anyway, I meant to say that I'm lucky to see 3 or 4 of these ole 600's a year.
WOW I need to get to this site more! Basically the driving pulley, which Bobcat calls the roto-swivel, is bolted to the shaft of the engine. One half of the sheave is bolted to the crankshaft through the center, the other is free to move from the crank out to the retainer. A hydraulic chamber is attatched to a graphite rotating seal, and is connected to a hose running to the valve connected to the speed control lever. To access this you remove a snap ring and the outer plate comes off, then you can access the inside and see if the bolt is in place. It is common for mechanics to damage the bolt or not correctly tighten it, causing the bolt to fall out. This is an easy repair if it's just loose. As for not seeing a 600 series I do often as it's the machine I have had and used. It's just too difficult to get a good deal on a newer model.
