School me on the mechanical PTO
 

OK.... 123 is running pretty well, if still not stopping well, but we're going to live with that, since I don't want to make this my lifes work.

On to the Last Big Thing keeping me from using this bad boy. The PTO.

I've never used this particular PTO, (it was on the replacement engine) but I'm not sure I understand the operation. I've never had one apart though I've had full sized clutch/pressure plate/flywheel assemblies apart many times, so I conceptually know how they work.

Engine OFF:

With no pressure on the PTO button (via the PTO lever) the crankshaft of the engine and the pulley on the PTO are locked and turn as one (well, there's a bit of slop I'll attribute to the wear in the woodruff key or the crank ... I can move it about 5 degrees )

With pressure ON the PTO button I can move the pulley independent of the basket/crank, as I would expect.

That all seems right.

Now , ENGINE ON:

When I apply pressure to the PTO button via the PTO arm, and then wedge a 2x4 against the PTO pulley ( I have no belts / deck on this yet and I was trying to simulate the load of an actual deck) I cannot stop the PTO pulley.

I would think that the running behavior should match the static, in that the pulley should be stoppable when I have the PTO button pressed in? What am I overlooking ? Why shouldn't I be able to stop it since the clutch button is depressed?

( be easy on me, I'm an electronics engineer) :-) Button is adjusted correctly

Bad PTO bearing ??

:bigthink:

Keep in mind the PTO for the 123 does not have a brake. There's not much stopping leverage pressing on the button without an implement to drag it down.

Otherwise, make sure the bearing works freely and is lubed.

Thanks guys.

Since it's really easy to turn the PTO pulley in relation to the crank (it's not spin free, but I can rotate it easily with thumb and 1 other finger) with the engine off and the PTO depressed, I'd have thought that it would be simple to stop it in the same condition with the engine running, but that's not the case (I was pushing on the pulley pretty good with the end of a 2x4). Doesn't make sense to me, but again, I'm not a PTO expert.

I don't mind pulling the grill and trying to get the PTO off but I'm wary of the of broken/stripped set screws. I've got 'em soaking in Kroil.

If the 3 springs aren’t adjusted properly the PTO won’t disengage all the way.

If the engagement lever is adjusted properly , then possibly the clutch wasn't adjusted properly via the three screws and assembly gauge ? Try a rubber tarp strap hooked to the frame and up over the pulley as a belt would go and see what happens ? it should stop turning with engine running with a little resistance holding it if everything is right !:beerchug:

Well, that's what I thought too. I wedged in a 2x4 between the frame and the pulley on the exhaust port size, and I had it tight enough for the pulley to start the wood charring from the friction.


If I can get the double set screws out, I'll check it, but darned if I can figure out how it is it's free with the engine off (I can easily rotate the basket in regards the PTO itself so the holes line up for the set screw) .

Strange!

Yea , something's not quite right ! The PTO on my 109 will pretty much stay put without a belt on it. It will be interesting what you find! Blow those set screw holes out with air if you can, and they should come out if you have soaked them. Unless, someone before has them boogered them up!

:beerchug:

I have seen PTO's that were working perfectly fine, and then from sitting in a neglected state wouldn't even dis-engage because rust and dirt crept in between the plates and disc.
Even though you have the "button to button" gap adjusted correctly, you still need to develop an air gap between both plates and thd disc when the button is pushed in.
I think you need to get it off and apart, cleaned up, and adjusted correctly, and you will be OK.

Be sure when you do all that you check for a broken or missing snap ring on the pulley.