simple,easy answer..

Allows for higher profit margins....

 less parts..more money made

there's probably 10-20 parts to make a throttle cable assembly and attach it to the engine and handle. a LOT of 'steps' that some $$$ priced HUMAN has to do.

Also NO inventory needed for the cable, mtg screws,etc. less $$$ HUMANS in the assembly line...

BTW I use old battery jumper cable ends on the bailbar.

Jay

Hold on now, let's think about this.  It was probably done out of necessity, how many lawn mower purchasers in the city do you think are smart enough to run a throttle? 1 out of 10, 3 out of 10?

Same reason they have that safety shut off on the handle, do you really think most of them would know to shut off the engine before they sharpen the blade?

I have a Z-turn that instructions say to always operate at full throttle. 

GOOD GOLLY, GAWD Almighty!!!  HI Les!!

You been gone on here longer than I have!!  Nice to see your smiling face again!!!!!

This'll make Joe's day!

Can't help on the stupidity of why on the lawn mower.  Somehow though, it must be to protect the idjet that can't figure out how to start the mower.

WHY are we protecting these people??  Let's just thin out the gene pool and be done with them.

Les Royer wrote: Now mr 99, I don't think we've met but everybody knows that if you leave it running, you can throw a wrench on that crankshaft and you can save yerself a whole lotta time by not having to drag out that air hose. By the way, hello again everybody!

WELCOME Back Buddy!!  Are you going to Hutch this year?  Would be nice to see that smiling face again!  And it's the GOTO this year also!!

Shamers hasn't relented and said yes as yet,,,,,,but if'n he don't.........theres a BUNCH of us that know where he lives.....

The "safety mechanisms" and the engine throttle are two different subjects.

The hand-op throttle is actually a 'variable governor' setup... the governor is usually a vane in the cooling duct, that as engine speed increases, airflow off the flywheel blower increases, causing the vane to reduce engine speed.  Just governance to prevent overspeed. 

They got clever, and incorporated a cam into the throttle lever, so that at a certain position, the choke would close.  Governor vane motion would partially open the throttle to allow it to continue running (without stalling from overrich, right?)... then they added a contact in the throttle control arm that when pulled all the way PAST idle, it'd short the magneto, shutting it down.

the REASON for being able to throttle down, was strictly for warmup of a cold engine.  An air-cooled engine relies on forced airflow, and the flywheel blower's speed creates the airflow pressure for that function.  When you slow the airflow DOWN, the engine warms up faster... and that warms up the intake (which is where frost forms on startup).  By having a SLOW speed, a cold engine can start and warm, and then be brought to full goverened speed to work.  At full goverened, the blower will push enough air through the shroud to keep the head and cylinder cool... at least, as long as it's not full of mice and grass clippings, right?

Problem is, cutting grass with a rotary blade is a 'velocity relative' operation... tip speed is important... too fast, and you'll dull the blade rapidly, too slow and the blade won't cut effectively... so running it at some point other-than-optimal (for the blade length, and cooling RPM) results in poor performance.

So they set 'em up to run at a fixed speed, like a generator. In doing so, the governor maintains a more stable speed anyway... nature of the design of a fixed vs. variable speed gov.

Now, as for the safety bail on the handle...  as they term them "Compliance Engines" (they 'comply' with safety regulations), the safety bail either kills the ignition and applies a spring-brake against the flywheel, OR... it disengages a drive clutch to the blade, and applies a brake, to stop the blade.

The INTENTION, is to stop the blade fast in case something happens... to keep people from getting hurt.

Bear with me here for a minute...

The flapper on the back of the deck... it's purpose is to exclude a person's foot IF they happen to slip into the mower from the rear.

The SAFETY GAS CAN's purpose is to protect individuals from the result of spills, leaks, and venting.

the AIRBAG's purpose is to prevent you from smacking solid surfaces in a car, in the event that you're in a crash, and not adequately restrained.

the SEAT BELT's purpose is to keep you from being thrown from the car for same.

The WARNING STICKER on the side of your McDonald's Coffee Cup's purpose is to protect you from being burned by hot coffee.

The real answer, is that none of the advertised purposes is actually TRUE.

The ACTUAL purpose of the bail on the mower, is to prevent the manufacturer from being fined by the federal government for not having a bail on the mower.  The bail, in reality, serves no effective purpose at protecting the operator, because, in the course of an accidental circumstance (a loss of footing or control), the instinctive reaction, is to HANG ON to the mower, so one doesn't slip into it.

The ACTUAL purpose of  flapper on the back of the mower's deck, is to prevent the manufacturer from being fined by the federal government for not having a flapper on the back of the mower... because, in the circumstance of a slip towards the mower, the operator, holding onto the handle and bail, causes the back of the mower to rise, and upon foot striking the bail, it folds UNDER the mower, providing a nice, easy, directed path for a foot to slide under.

For anyone who doubts these statements, send me an email, I will send you a picture of my left foot, as BOTH of the above statements are true to that circumstance.

As for the safety can...  since the contents of a common gasoline can expands and contracts with both ambient temperature and atmospheric pressure, the total elimination of venting is, in reality, much worse than what we USED to have.  They now 'spew' violently combustible spray upon opening... and since these cans are now basically all plastic, a combination of expansion, contraction, UV and GASOLINE exposure embrittle and cause them to crack, which results in them bursting ON THEIR OWN... something our old vented steel cans NEVER DID.  Let's hear it for the 'safety' hawks.

As for the airbag...  there's circumstances where they work... and just as many where they don't, and some where they do more harm than good... and as we've found (with Takata) the opportunity cost, over the LONG TERM, was totally misrepresented.  If a person wants to buy a Jeep, and they don't want airbags, that's their call.  ABS, 'traction control' and 'dynamic stability control' is in the same category... people that know how to drive, not only don't NEED those 'features', they can be endangered by systems that either fight, or totally take away, control which they would otherwise be able to maintain BETTER than a system which cannot see and understand what lies immediately ahead.

As for the seatbelt...  if a person chooses to not wear one, that's no fault of the manufacturer.  I always do... unless I'm driving on a frozen lake.

As for the warning on the coffee cup... the circumstance of a coffee drinker (which I am not) seems to prefer coffee to reach them in an excessively hot state, so that once it cools to the preferred temperature, they can drink it, and usually (in winter anyway) provide internal warmth.  I have been advised by my crushed-bean-drinking comrades, that most fast-food organizations have, for obvious reasons, resolved all this liability by simply serving lousy coffee, cold... even so much as to advertised it as "Iced Coffee" in an attempt to commerciallize what they feel least risked-by.

I will tell the future:

Someday, someone will be driving a car, and some 'system' will detect an unsafe condition, and 'take control' away from the 'driver' in an attempt to recover... and when that happens, and the circumstance results in serious injury or death, the driver will be placed on witness stand.  The lawyer will ask 'What did you do', and the DRIVER will answer "Nothing... because I could do nothing- the car's systems took away control".

At that point, the CAR, and it's MANUFACTURER, and the programmers of the systems, will now be liable for all injury and damage done by the car.

Perhaps sensibility will prevail once 'safety organizations' become the conduit of liability. it is Personal responsibility, not Regulation, that is the Alpha, and the Omega of true safety.

Stupid Machines for stupid people that have NO PURPOSE driving them.  Followed a SWIFT Transport truck into a local store lot, driver was catty and nervous, HAD TO back to the dock on his Blind Side ALL BY HIMSELF, had not EVER done it prior(Quoted as Had Passed a training school).  Finally after three aborted attempts gave up and had the store personnel unload in the lot with a fork truck.

Presence of lack of choke and throttle are NOT mandated...

But evolution of design excused them from existance.