Murray (MTD) 30" Rear-Engine Rider

[1saxman]

This model but a Murray:



I noticed the deck shaking like the blade was out of balance but when I took it off, it was in great condition and balanced fine. I had a new blade so I went ahead and balanced it before installation and it was pretty far off. Anyway the result was an improvement. I used it this morning and everything was fine.
Now, the problem; during this period of working on the blade, I noticed that turning the blade with the blade drive disengaged took some effort and produced a scraping sound. So I'm wondering if this mower has a blade brake that activates with disengaging the blade drive. I ran it to test without the blade and it was perfectly smooth and quiet when I engaged it, and I couldn't detect any play in the spindle - so even though I don't understand why the deck shakes with the blade engaged, especially at lower engine speeds, there doesn't seem to be any real problem.
I just want to clear up if there's a blade brake on it. Any thoughts?

 

[bertsmobile1]

Yes
US safety laws require all blades to have a brake

 

[1saxman]

Well, that explains it! Thanks

 

[Forest#2]

I was recently given one of them Murray RER's. Model 13DC26JD058.


I eventually found on-line after lots of searching a IPL and owners manual, separate items.

Yes it has a blade brake and when trying to turn the blade by hand will usually produce a scraping sound.

You have to be careful when re-installing the star type blade so as to get it positioned properly onto the mating star spindle or you will get a vib.
If the blade has hit something solid it's common for the star on the spindle shaft to shear requiring a new spindle shaft. (I had to install new spindle shaft on this one leaving the spindle housing in place after removing the deck)

Those decks do not have any anti-scalp gauge wheels so the mower is basically a flat ground mower I installed a block on the deck height lever so the deck would not go too low to the ground. This deck blade will drop down to within probably 1/4 inch of the ground.
This one also has a safety switch on the deck discharge chute that has to be un-plugged when removing the deck. If the chute is removed the PTO won't en-gauge. (strange one)
This one also does not have the safety seat switch to kill the mower when PTO is en-gauged if the OP leaves the seat. Not even wiring or switch for such.

I will have to install such before selling the rig. or just use the rig for parts.
Has a really good Briggs wimpy/weak built 21 series 10 hp engine and the engine does not even bump the governor when mowing tall grass and starts so fast electrically it's scary, instant start hot or cold.

 

[1saxman]

'You have to be careful when re-installing the star type blade so as to get it positioned properly onto the mating star spindle or you will get a vib.'

You'd have to be pretty ignorant to not realize that the blade is not indexed before tightening. Yep, that would be a major vibration.

'Those decks do not have any anti-scalp gauge wheels so the mower is basically a flat ground mower I installed a block on the deck height lever so the deck would not go too low to the ground. This deck blade will drop down to within probably 1/4 inch of the ground.'

I use max deck height or 1 notch down, which gives me the equivalent of 3" on the trim mowers. From what I have seen, most rider owners tend to wait too long to cut, then cut too short with a lot of dust and scalping. That's pretty destructive to the turf, even a bunch of weeds like mine.

My mower is about 5 years old and it has the 344cc engine that also is ample power for this machine. I wish it had a quieter muffler though. Somebody gave me an old Craftsman yard trailer that I'm going to fix up and use. I can then move dirt around where needed and haul short logs out of the woods where the truck can't go. The weakest part of this mower is the really crummy steering arrangement but considering I got mine from Walmart on sale for $600, I can't say too much bad about it.

 

[bertsmobile1]

'You have to be careful when re-installing the star type blade so as to get it positioned properly onto the mating star spindle or you will get a vib.'

You'd have to be pretty ignorant to not realize that the blade is not indexed before tightening. Yep, that would be a major vibration.

I regularly find then not fitted properly
happens when Joe Average holds the blade with one hand while they do the nut/ bolt up all the way with a rattle gun
The star is not hard but the blade is so it can shave a tiny fraction off the edges of the star which then get trapped under the blade so the blade ends up being angled.
I have cleaned so many of these up with an end mill in the Dremel tool it is not funny .

 

[Forest#2]

bertsmobile said
I regularly find them type blades not fitted properly also.

Same here.
I see such quite often especially when the spindle shaft itself stars are partly distorted from the blade hitting a hard object and displacing the steel on the shaft and at the blade and someone removes the blade and does not pay close attention that the spindle shaft and maybe the blade needs to be replaced to get a balanced true blade re-install operation or just simply tries to ignore such. Blade not only offset to each side but not same height at the tips. (and some blades have a H pattern that also fits onto the star pattern and this type distorts even more readily.

about your question about blade brake scraping noise.
If the blade brake pad is worn out the scraping sound you are hearing might be metal to metal contact and the brake pad assembly needs to be replaced. You can inspect such by dropping the deck all the way down and using a flash light and looking at the pad when the PTO is on so as to expose the brake pad. It's also a common thing for the blade brake pad to be worn out and metal to metal contact. (and your jaw will drop when you price the replacement assembly) and requires that the deck be removed for brake replacement.

 

[1saxman]

Thanks for the info on the brake. I guess it could be worn out if something is out of whack and it never releases. Not many hours on it.