ZD326 blade stops turning when in high grass

Brown Dog · Jul 21, 2023

Sounds like the 2 coned spring washers have flattened out
OR
you don’t have the components assembled correctly.

tallyho8 · Jul 23, 2023

Now that my blades are on tight, I have a new problem. I started to cut grass yesterday and the same blade was loose again. I had only cut for about 5 minutes. I drove it to my shop to work on it, turned the key off and it kept running. I looked for wires to pull to kill it and couldn't find any that killed it. I took the key switch off and unplugged it but it kept on running. I sat back and tried to think of a solution to kill it. After about 5 minutes, it started missing out and sounded like it was running out of fuel although the tank was almost full. Then it killed.

I waited a few minutes then hit the starter and it started right up. I turned off the key and it killed and has worked fine since. Anyone know what could have made it refuse to kill?

Brown Dog · Jul 24, 2023

98ft lbs on those small 10mm threads sure seems excessive

Is ZD326/331 the same setup as ZD1211 in the pic illustration in post #5 ?

Midniteoyl · Jul 24, 2023

If you havent yet, try new bolts. Those may be too stretched.

4570Man · Jul 24, 2023

LittleBill21 said:
what a dumb design, the blades aren't keyed?, I would torque the cup washer to blade at the proper torque, then I would weld the cup washer to the blade itself. Ridiculous design.

Basically all zero turns along with virtually all other riding mowers use round hole blades. I don’t know what bases for comparison you’re using to say it’s a terrible design. I would venture to say the Kubota zero turn is the strongest design on the market. Kubota has a shaft drive deck. Basically all the others use a drive belt that slips under high load. The Kubota uses a double belt to drive the blades that’s last upwards of 1k hours. Virtually all the others use a single belt that only last a few hundred hours. The Kubota blades use a splined washer on the blade that’s better than just a regular bolt that virtually all the other zero turns use.

4570Man · Jul 24, 2023

Brown Dog said:
98ft lbs on those small 10mm threads sure seems excessive

Is ZD326/331 the same setup as ZD1211 in the pic illustration in post #5 ?

The illustration in post 5 says 98-117 newton meters. If I translated right the top end of that chart at 117 is 86 foot pounds.

4570Man · Jul 24, 2023

RjCorazza said:
Assuming the op has the bellview washers oriented correctly, I would be inclined to torque the bolts a little more. Perhaps add a 3rd washer and increase the bolt torque if there is enough thread (I've never added a 3rd washer).
I don't use a torque wrench on the blade bolts for my zd326 or zd1211, but I'm sure I keep them tighter than 98 ft/lbs.
I take the blades off to sharpen every 2 weeks or so, and have never had a problem with them.

You’re way over doing it with in excess of 100 ft pounds on a 10mm bolt. The blade bolts are self tightening anyway. I only put mine on snug and they never slip.

LittleBill21 · Jul 24, 2023

4570Man said:
Basically all zero turns along with virtually all other riding mowers use round hole blades. I don’t know what bases for comparison you’re using to say it’s a terrible design. I would venture to say the Kubota zero turn is the strongest design on the market. Kubota has a shaft drive deck. Basically all the others use a drive belt that slips under high load. The Kubota uses a double belt to drive the blades that’s last upwards of 1k hours. Virtually all the others use a single belt that only last a few hundred hours. The Kubota blades use a splined washer on the blade that’s better than just a regular bolt that virtually all the other zero turns use.

virtually all? I have personally seen it once, I have worked on maybe 50 different riders over my years, and all of the ones I worked on had a star variant stamped blade which is what kept it in place on the on the spindle from slipping, that said I have not worked on more industrial machines, usually lower end consumer grade stuff.

I have multiple machines on a single belt at close to 1k hour with no wear, so not sure I agree there at all

Midniteoyl · Jul 24, 2023

4570Man said:
Basically all zero turns along with virtually all other riding mowers use round hole blades. I don’t know what bases for comparison you’re using to say it’s a terrible design. I would venture to say the Kubota zero turn is the strongest design on the market. Kubota has a shaft drive deck. Basically all the others use a drive belt that slips under high load. The Kubota uses a double belt to drive the blades that’s last upwards of 1k hours. Virtually all the others use a single belt that only last a few hundred hours. The Kubota blades use a splined washer on the blade that’s better than just a regular bolt that virtually all the other zero turns use.

Never had a round hole blade that didnt also have pin holes. My ZT uses pin holes.

ROUSTABOUT · Jul 24, 2023

Midniteoyl said:
Never had a round hole blade that didnt also have pin holes. My ZT uses pin holes.

Heavy duty commercial has round holes. I kept sharp blades handy and changed 66 blades a week. Basically half the mowers every other day. Kept a few new blades to replace ones too worn. They'd wear in two on the back side where they turned up. I welded some of those back and used them again.