Kubota Z421 - Hard to get blades spinning.

[slomo]

Ya know, just because we are on here looking for information does not mean that we are stupid.

It was no surprise the FRIEND couldn't find a problem. Nothing about anyone being silly.

We checked the play in each spindle, they only have 207 hours on them, unlikely that one of them went bad, but we checked them anyway. You don't need to be a detective to understand when a bearing is going bad.

Hours mean zero in mowers. People can tear up an anvil in record time. Play is only one factor in bearings being good. See that CSI reference stuck. Good for ya'.

My only complaint is that I have to be 1/2 throttle and up to get the blades to start spinning

Totally normal. Three blades and bearings at a dead stop takes some Gundy to get going.

You know you are supposed to be mowing, running, idling at MAX revs all the time right? As in 3600rpm soon as you let go of the key?

Is this an air cooled engine? If so better keep the revs up.

 

[BIGBREW]

No surprise.

How about the spindle BEARINGS which the lawn crew owner, could not see, unless he gutted the spindles from the deck CSI style. With the belt off, do all the spindles rotate smoothly and silently?

Should be more than enough if Kubota made it that way.

Probably running on one dead cylinder.

No, but when I pull it out to mow this week, I will definitely check that. Thank you.

 

[Auto Doc's]

Seems that some folks went off on a tangent about spindles but missed the fact that you are trying to engage the deck at idle or near idle RPM.

Don't get me wrong, checking spindles is very important and they do have issues, but noise would be obvious when the deck was run for any length of time.

 

[StarTech]

Not all deck spindle problems make noise. Ever had plastic baler twine jam in the spindles?

What was mention was there were a startup stalling sound which can be either the PTO clutch slipping under the initial start up load or the belt slipping under the start up load.

 

[BIGBREW]

Seems that some folks went off on a tangent about spindles but missed the fact that you are trying to engage the deck at idle or near idle RPM.

Don't get me wrong, checking spindles is very important and they do have issues, but noise would be obvious when the deck was run for any length of time.

I ran on old Simplicity 61-inch zero turn before this one. That one you could pull the pto at a pretty low rpm. Guess I am just getting used to the new one yet. I went from hay wagon to suspension seat, so this is quite an upgrade for me. Just want to make sure I am running the new mower properly. Thank you for the input.

 

[Auto Doc's]

I ran on old Simplicity 61-inch zero turn before this one. That one you could pull the pto at a pretty low rpm. Guess I am just getting used to the new one yet. I went from hay wagon to suspension seat, so this is quite an upgrade for me. Just want to make sure I am running the new mower properly. Thank you for the input.

Was that Simplicity a hand operated lever PTO?

 

[BIGBREW]

Was that Simplicity a hand operated lever PTO?

No, it was a pull switch. They would just engage pretty easy is all. Guess I am just not used to my new one.

 

[Tiger Small Engine]

I ran on old Simplicity 61-inch zero turn before this one. That one you could pull the pto at a pretty low rpm. Guess I am just getting used to the new one yet. I went from hay wagon to suspension seat, so this is quite an upgrade for me. Just want to make sure I am running the new mower properly. Thank you for the input.

How fast the engine is running to engage the PTO is another topic that many people disagree with. I have been hitting the PTO on my Scag at wide open throttle now for almost 2000 hours (original PTO clutch). Your mileage may vary.

 

[Auto Doc's]

Hi Tiger SE,

I have likely heard most of the traditional debates. (LOL)

The ones who disagree have likely never measured the charging system output to compare idle versus full throttle. You have an electric PTO.

How quickly and firmly an electric PTO engages depends heavily on having high charging system output, the highest system output is at full throttle.

Some people like to claim high RPM creates excess "shock load" on the deck belt and spindles but I just cannot find any proof to support that (armchair) opinion.

Being a 40+ year (certified) technician has taught me that it is better to put the (imagined) shock load on a cheaper to replace deck belt than the expensive engine.

 

[slomo]

As Auto Doc was hitting at, at low revs, could be insufficient voltage to fully engage the PTO. Makes total sense.