Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions

MowerMike

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions

Although there is already an existing thread for this lawn mower, I wanted to make sure everyone who owns it sees this post to prevent damage to the mower when removing/replacing the blades.

Specifically, the maintenance instructions starting on page 25 of the English Owner's Manual state that the two blades labeled Blade I and Blade II are removed by turning the mounting nut clockwise (left-handed thread) for Blade I and counterclockwise (right-handed thread) for Blade II. In fact, the complete opposite is the case with the mounting nut for Blade I loosening counterclockwise and Blade II clockwise. I've visited the Greenworks website and viewed the online Owner's Manual, and it still contains the same errors.

The interesting thing is that the markings on the original blades for loosening and tightening the mounting nuts agree with the Owner's Manual, however, the markings on the replacement blades are reversed and agree with the actual configuration. The replacement blades were purchased at my local Lowe's under the Kobalt brand name, however, the part numbers stamped on the blades are identical to the Greenworks part numbers as listed in the manual (33307486 for Blade I and 33308486 for Blade II). Since I did not purchase the Greenworks branded blades, I can't say whether the markings have been corrected on them. Based on the directions that the blades are turning, it makes sense that the nuts would tighten as they do and not as stated in the manual to prevent them from loosening during operation.
 
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1 Lucky Texan

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Re: Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructio

just now seeing this, good catch
 

daveman

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Re: Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructio

MoverMike is exactly right!!! The instructions for my mower were the opposite to loosen the nuts on blade 1 and blade 2.

I bought my Greenworks 25302 April 2013. I previously tried to remove the blades to sharpen them, but since I couldn't get them off I ended up just sharpening them with a small file in place.
That worked fine, but since I've had the mower for 4 years now I wanted to replace the blades.

FYI: I purchased the replacement blades; Greenworks 29712, 10-inch blades for my mower model, from Amazon for $17.

I used a pair of large vise-grips to hold the square metal washer to the blade as I turned the nut, along with the wood brace. Because MowerMike pointed out the error in the instructions I was able to remove and replace the blades. I cut the grass afterwords and the replacement blades worked great.

Another FYI: I had so much grass around the nut the socket wouldn't stay in place on the nut. So I took a wire brush to the nut and surrounding area. Stand back a bit or wear a facemask as this process produces a lot of grass dust.
 

Pumper54

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Re: Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructio

Interesting thread, I don't have an electric mower but this peaked my interest and here is what I found at the Greenworks website for the 25302 manual:

For the
BLADE I , loosen the blade nut by turning it clockwise (as viewed from bottom of mower) using a 15 mm wrench or socket (not provided). For the
BLADE II, loosen the blade nut by turning it counterclockwise (as viewed from bottom of mower) using a 15 mm wrench or socket (not provided).

Seems that they have not made the corrections needed. I wonder how they are labeling Blade 1 and 2, is that from the operator's view or from the front view of the mower?
Tom
 

MowerMike

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Re: Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructio

Seems that they have not made the corrections needed. I wonder how they are labeling Blade 1 and 2, is that from the operator's view or from the front view of the mower?
Tom

Actually, the blades themselves are labelled Blade I and Blade II with arrows and padlock symbols to indicate the loosening and tightening directions. The blades are also mislabelled and cannot be installed on reversed sides of the mower deck. The images in the manual are very clear as to which blade is I and II. The problem is typical of Greenworks documentation, which is rife with errors that are never corrected. I recently bought one of their chainsaws which incorrectly specified the chain as 0.050" gauge when in fact it was 0.043" gauge, resulting on my wasting $11 on the wrong chain.
 

1 Lucky Texan

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Re: Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructio

they design stuff like this such that the rotation direction will tighten the nut so, the shaft with the 'typical' righty-tighty threads and nut, will spin CCW . that means the blade with the cutting edges moving forward if rotating CCW AND with the little turned-up vanes pointing up into the deck, goes on that shaft.

I never really paid much attention to the manual so - this is an important thread for folks relying on it, thanx MM

I recently had to buy some of the plastic holders for the blades, mine have cracked edges. Got them from some place on ebay.
 

MowerMike

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Re: Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructio

they design stuff like this such that the rotation direction will tighten the nut so, the shaft with the 'typical' righty-tighty threads and nut, will spin CCW . that means the blade with the cutting edges moving forward if rotating CCW AND with the little turned-up vanes pointing up into the deck, goes on that shaft.

I never really paid much attention to the manual so - this is an important thread for folks relying on it, thanx MM

I recently had to buy some of the plastic holders for the blades, mine have cracked edges. Got them from some place on ebay.

I think you will find that the nuts on that mower tighten in the wrong directions, such that the CW rotating blade (Blade II) tightens CW, and the CCW rotating blade (Blade I) tightens CCW. The instructions and blade markings are the way it should be done, but the shafts on the motors were reversed in terms of proper bolt threading. It really doesn't matter, since blade alignment pins on either side of the bolt prevent the blade from moving and potentially causing the bolt to loosen.

So, perhaps the manufacturing error has been corrected in later production runs, such that the manual instructions and blade markings are now correct !
 

1 Lucky Texan

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Re: Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructio

I think you will find that the nuts on that mower tighten in the wrong directions, such that the CW rotating blade (Blade II) tightens CW, and the CCW rotating blade (Blade I) tightens CCW. The instructions and blade markings are the way it should be done, but the shafts on the motors were reversed in terms of proper bolt threading. It really doesn't matter, since blade alignment pins on either side of the bolt prevent the blade from moving and potentially causing the bolt to loosen.

So, perhaps the manufacturing error has been corrected in later production runs, such that the manual instructions and blade markings are now correct !


!!!!

I'm gonna check tonight.

the forward motor turns CCW (as viewed under the mower) so, I may be mistaken as you point out.

(kinda does make one wonder if there was a manufacturing error that they just passed thru..., or, there's some concern about loosening from 'precession/nutation' like bicycle pedals???))
 
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MowerMike

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Re: Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructio

the forward motor turns CCW (as viewed under the mower) so, I may be mistaken as you point out.

(kinda does make one wonder if there was a manufacturing error that they just passed thru..., or, there's some concern about loosening from 'precession/nutation' like bicycle pedals???))

I think you are giving the Greenworks design team too much credit for thinking this out beyond conventional practice. Why would they do things differently than all their other mowers, not to mention just about every other rotary blade mower on earth, which use a CCW rotating blade and a CW tightening nut or bolt. Also, your bicycle pedal comparison is a totally different loading situation, since a bicycle pedal imposes loading transverse to the shaft, whereas a blade does not.
 

1 Lucky Texan

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  • / Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructions
Re: Warning ! Serious error in Greenworks 20" Dual Blade Mower Maintenance Instructio

any way, it IS important for folks to get the blades with aerodynamic tips facing 'up' towards the deck and the cutting edges facing the cutting direction of course.

(won't be able to see my mower for a coupla hours but, is there no way to go back and edit anything I have typed that is incorrect? I don't like that I seem to have muddied the water here))
 
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