deuce accessory switch handle - weird shape?

[maddawg308]

Okay, I know I already asked a stupid question this weekend, but I have a good one: why does the deuce accessory switch look like the weird red-headed stepchild it is? All the other switches and knobs on military equipment are pretty simple and standard, only this switch looks like an arm broken in three places.

No reason I need to know, I was just looking at it the other day, and it puzzled me as to why....

 

[dm22630]

When it is in the "on" position, it will hit the shutoff cable if it is still pulled out.

 

[FreightTrain]

Yep.You gotta turn it off to pull the engine kill and you cannot push teh engine kill in if the switch is already on.Plus the little tab on teh right is actually the handle.I just use the broken arm thingy.One of those thing over Engineered for the purpose......but then again,strange things can happen when you got 18 year old throttle jockeys straight outta high school and bootcamp!

 

[zoomiefog]

Okay, I know I already asked a stupid question this weekend, but I have a good one: why does the deuce accessory switch look like the weird red-headed stepchild it is? All the other switches and knobs on military equipment are pretty simple and standard, only this switch looks like an arm broken in three places.

No reason I need to know, I was just looking at it the other day, and it puzzled me as to why....

I was wondering the same thing. Love the avitar BTW.

 

[cattlerepairman]

I am sure there were...interesting...incidents to make the military want this.
I am wondering...do all the M35 have this oddly shaped switch, including the gasoline powered trucks? Or is something specific to the multifuel?
I suspect, for consistency, they all have it, but I wonder where the problems arose. Is it an electrical issue that the alternator/generator does not like it when the accessory gets shut off with the engine running? It may cause issues with excitation the next time round.

My Detroit diesel KW has a warning label that states to pull the engine shutdown FIRST and THEN switch off the accessory/starter switch.

 

[msgjd]

We who were actual military truck school students were taught during the 4-6 week MTOC (and subsequent TM's and PS Monthly articles) that the engine kill knob on multifuels is to always remain pulled out after shut down, transmission neutral, parking brake set and holding, wheels and trailer chocked if neccessary. (of course chocks worked real well in mud ) Thus when someone gets back in the truck and flips the accessory switch to crank it, the crooked thingy is to block us blockheads from pushing the engine stop lever in before cranking the engine.. That is the reminder to turn the engine over with it pulled out, to check for hydrostatic lock .. 5-ton multifuels are also supposed to have that style accessory switch lever for the same reason .. The additional reason why the military wanted the engine stop lever to remain pulled out at all times after shutdown (and tranny in neutral) is because the multifuels WILL START if left in gear if towed, bumped, pushed, or happen to roll unattended down a hill with the knob pushed in, regardless of the accessory switch position

 

[msgjd]

I am wondering...do all the M35 have this oddly shaped switch, including the gasoline powered trucks? Or is something specific to the multifuel?

you guessed it, the weird lever is specific to the multifuel deuce and multifuel 5-ton .. Likewise, all gassers that were remotored with a multifuel were supposed to get their normal-looking accessory switch lever replaced to the "weird" style..

I do not remember Mack-powered A1's to have the weird acc switch lever, my last time with any real A1's was 40 years ago.. But one oddity I remember is they had a flat-faced round black knob to kill them, not a typical T-handle like multifuels

 

[msgjd]

I am sure there were...interesting...incidents to make the military want this.

yes there were/are reasons for it.. The major reason is the possible situation of hydrostatic lock in multifuels .. Crank that engine while providing fuel and if even just one cylinder has liquid trapped while the engine has firing power providing torque and momentum during cranking, you will get Incident #1 : BANG ! Soldier has successfully busted a piston, or most-likely, soldier has successfully completed task of bending a rod(s) on the errant cylinder(s) which can lead to more-serious damage before engine gets shut down .. The idea is/was , if soldier cranks engine without providing fuel, the starter by itself is not strong enough to break engine nor bend a rod if any cylinder has a liquid obstruction.. The piston will supposedly stop, starter stalls and goes GRRRRRR, perhaps melt a battery post to make the event just a little exciting.. Personally never had it happen but it had happened a time or two in my last BN.. We all know Murphy. The one time we fail to check for something is the time it can F-up..

As far as electrical reasons, I know what you mean.. Have had construction equip that prefers the switch turned off before pulling the kill lever, and vice-versa.. However, in the army of my experiences, we never discussed if there was any electrical reason.

It was always about hydrostatic lock in multifuels, and also, Incident #2 , Soldier fails to leave kill knob pulled out at all times after shutdown with truck in neutral w/brake set, chocks if not on level terrain.. Explanation: multifuels will start and drive off by themselves if the engine stop is in and they are parked in certain gears, regardless whether the acc switch is off or not.. Of course they need gravity or an accidental push or whatnot to get them rolling, but it did happen here and there

 

[Zoyd AT1]

Well that explains the Logical, Safety and Operational Reasons, but why isn't it painted? Never mind. Thanks msgjd, great response.

 

[msgjd]

Well that explains the Logical, Safety and Operational Reasons, but why isn't it painted?

painted? .. but they are .... OD, flat green, flat sand, whatever the base color of the vehicle is.. For anything to be painted red other than a fire extinguisher on a tactical vehicle is a no-go and will earn a unit a gig during their Brigade IG inspection