PeteFree.com2008 Lawn-Boy Platinum 21 Inch Mulching/Rear Bag Convertible Self-propelled Lawn Mower: Model 10797 - Review
© 2011 Peter Free
17 August 2010 (Updated 23 March 2011)
Lawn-Boy 10797 mower is not recommended
This blade-clutch-equipped, self-propelled lawn mower is a grossly over-priced, undependable loser. It is a recipe for frustration and expensive repairs.
I have the same opinion of the Honda engine that it comes with.
This review is based on two samples of Model 10797.
Your opinion may differ, given different working conditions
I have a farmer’s mentality. I expect equipment to operate properly and for long periods, under less than perfect conditions.
A lawnmower is essentially just a gasoline motor on a housing mounted to a cutting blade. There is no acceptable reason why such a simple machine cannot work reliably.
Test conditions (two easy seasons)
I used the Lawn-Boy to mow the less challenging 0.7 acres of a 1.3 acre parcel.
Engine hours averaged from 2 to 5 hours per week during the nine to ten month mowing season.
I used the mower exclusively in a mulching mode.
Summary of mower problems
The first sample of Lawn-Boy’s Model 10797 ran for less than two hours before the engine would not run with the blade engaged.
The dealer could not diagnose the problem and replaced the mower with another.
The second unit developed the same problem after two summers of use. I worked around that problem by raising the wheels to maximum height.
However, the Honda carburetor began failing toward the end of the 2010 season, running erratically and often stopping completely. The engine failed to start at all in March of 2011, despite proper winter storage.
Diagnosis demonstrated that the carburetor needed to be replaced.
Two summers of easy-as-pie use, and the carburetor fails?
Engine and cutting performance
The Lawn-Boy Honda engine started easily (when its carburetor was working) even when hot. However, the Honda motor is too finicky about mowing conditions to be considered a good design.
Poor performance typified all three samples of Honda mower engines that I have owned, including a 2006 commercial-use Honda push mower and both samples of Lawn-Boy’s Model 10797.
Honda engine problems included:
(1) Sensitivity to light debris on the paper engine filter.
The engine begins to run unevenly, when its filter has relatively little pollen or dust on it. These filters are not cheap.
In contrast, low-end Briggs & Stratton foam filters are washable and have to be really clogged before their engines stop running. They can be washed, re-oiled, and reused multiple times.
(2) Sensitivity to cutting blade straightness.
If I put even a slight bend in the cutting blade (by hitting an obstacle), the Honda engines lost power and ran unevenly.
In contrast, inexpensive Briggs & Stratton engines exhibit no sensitivity to even massive blade deformations. If the cutting blade can still turn without hitting the ground, Briggs & Stratton engines will turn it normally.
(3) Tilting these Honda engines toward the air filter side ruins the paper air filter by soaking it with oil. The engine will not run at all after that happens.
On level ground this characteristic is not a problem. On sloping, obstacle-strewn ground, it can be.
(4) All three Honda engines displayed a tendency to quickly come out of tune, even under light use. This manifested in oscillating idle speeds when not under load.
Non-engine performance ─ good points
The Lawn-Boy’s self-propelled drive is outstanding.
Its Sens-a-Speed Self-Propel® system works exactly as advertised. The system is built into the mower handle and continually adjusts itself to the operator’s walking speed.
One can also drag the mower backward without difficulty.
Deck height is adjusted with flexible levers at each wheel. The levers are sometimes difficult to move from setting to setting. I usually use two hands with the engine turned off.
The mower’s toy-like plastic wheels held up to Oklahoma’s bumpy concrete-like clay.
A step-on, pedal-operated, folding handle is another outstanding feature. It much reduces the storage volume that the mower requires. Despite the handle’s multiple joints, it never collapsed under normal mowing use.
Non-engine performance ─ bad points
Evenness of cut was generally good, provided tall or wet grass did not clog the mower deck.
The mulching deck worked well in chopping small pieces. But when grass is tall, thick, or wet, the deck clogs quickly. The Honda motor stalled frequently, no matter how slowly one walked, unless I raised the deck to its maximum height.
Tilting the deck upward (by pushing down on the mower handle, while the engine running) usually failed to fix the tall or wet grass problem ─ unlike other mowers I have owned.
The stalling problem was due in equal parts to the temperamental Honda engine and the poor design of the mower deck.
The deck’s failure to clear clogs is caused by its (i) low volume, (ii) swirl pattern, and (iii) surprising tendency to wedge almost immoveable clumps of grass between the tip of the blade and the deck housing.
Clearing these blade-wedging grass clumps out requires turning the engine off and, either tipping the mower onto its side, or removing the rear hatch and reaching inside.
The clogging behavior occurred with Bermuda, tall fescue, annual rye, and three kinds of volunteer/wild grasses on the property. I suspect it will also happen in thick or tall blue grass.
Blade clutch, also a pain
The Lawn-Boy’s blade clutch is also poorly designed.
It (or the mower’s electrical safety system) stops the engine from running properly, even when the clutch is only slightly fouled with vegetative debris.
The instruction manual implicitly admits this design flaw. It directs the user to periodically disassemble the blade clutch’s outer parts.
Disassembly involves removing the cutting blade, two spacers, and a shield. Then one has to blow debris out of the mechanism, which is accessible only through two small slots. I used canned air.
The blade clutch’s sensitivity to debris appears to be heightened in dry Bermuda grass.
Poor overall design results in difficult diagnoses
When the mower engine won’t run properly, it is difficult to tell whether the problem is:
(a) the Honda engine’s finicky temperament,
(b) the blade clutch being fouled, or
(c) the lawnmower’s overkill electrical safety locks acting up for no apparent reason.
Tedious electrical safety locks
The electrical safety system appears to be hooked to the (i) blade clutch, (ii) drive handle, and (iii) removable rear deck hatch (which can be removed for bagging).
The electrical interlock system is sensitive. It has no readout to tell the user where the problem is.
My second sample of Model 10797 went the way of the defective first
A little over two years after buying it, my second sample of the Lawn-Boy began exhibiting the same problem that the defective unit had.
The replacement mower would not run properly with the blade engaged for more than a few minutes after warming to operating temperature.
As an experiment, I tried several repairs in individual fashion. These included cleaning the blade clutch, air filter, rear hatch assembly, and tilting and tapping the carburetor.
The mower would resume running properly after each fix. But then it would begin stumbling and stalling again after about five to ten minutes of use.
The only commonality shared by all the fixes was that it took long enough to make them for the mower to cool significantly.
I began to suspect the ignition module was defective. Before replacing it, I decided to adjust wheel height, to see if that made a difference.
With the mower at its highest wheel height, it ran fine. (Previously, I had it in the middle and low-middle positions.)
My hypothesis is that the blade clutch assembly is poorly designed. When the mower heats up, metallic parts in the assembly expand enough for small bits of debris to trigger the stumbling problem (probably through the electrical interlock system).
When the blade is high, my guess is that:
(a) air cools the blade clutch assembly more effectively, and its metal parts don’t bind;
(b) the electrical interlock is not so easily triggered;
and/or
(c) the higher distance between blade and ground:
(i) reduces the force of the downdraft,
(ii) raises the deck volume,
and
(iii) decreases the velocity of debris that bounces off the ground and back into the blade clutch assembly.
Not recommended
Lawn-Boy Model 10797 is too finicky to recommend, even when it runs
When it does not run, it is diagnostically the worst mower I have ever owned.
After the carburetor died in the winter of 2010-2011, I donated the machine to a dealer.
Overall, the Lawn-Boy Platinum Model 10797 qualifies as the worst mower I have ever owned by several orders of magnitude. It was that bad.
Craftsman’s cheapest mower is better than this Lawn-Boy
A much better bet, although not self-propelled, is Craftsman’s bottom-of-the-line Series 550 push mower.
The bottom-end Craftsman costs one-third of the Lawn-Boy’s price.
It has out-performed and out-lasted three expensive mowers under conditions the fancier mowers were unable to cope with. It starts easily, runs evenly, and stops only when its air filter is completely clogged.
A farmer’s machine.