KO 2143 is not overkill, any other servo in ok on the throttle , you just need transmitter setting refinements, neutral or slight negative on failsafe will not strain the servo

The 2143 is meant more for steering because of the speed. It would be a terrible waste to put it on the throttle. For the throttle / brake servo, it is better to put a high torque servo although a little slower.

If any servo is left for very long time in fail safe position, it'll burn the motor out.

Correct:
High torque servo for throttle/brake application
High speed for steering application.

In any case, I suggest NOT using digital servo on throttle/brake application. Just my $0.02.
i dig a quick search of the web .. below are some info I found:

a) Argument 1:
A digital servo can fail in a way that is very hazardous for a
throttle control. They can stick in the WOT position and not respond to a return spring or a failsafe(!).

b) Argument 2 (open to debate .. depending on how you set up your car):
when you are on the track during warm-up for your mains, and you are over shooting the
turns because you need more brakes, what do you do? - pull off the track and skip the main? - no, you turn the EPA up a few clicks on your controller until your car has enough braking power, right? This in turn is putting a major strain on your throttle servo. digital servos work way faster and harder and draw more current than a standard servo. If you hold full brakes on for too long, the servo will overheat and fail.

c) Argument 3 - simply relates to how throttle servos are used:
When braking hard each time, you are more likely to keep the throttle servo at full lock for an extended period of time. Add the load of an accelerating buggy to that and you've got your servo working over time for that period.
With steering servos, you usually do not need to lock it at full steering and even if you do, you do not need to maintain it at that position for an extended time unless you want to go in circles


i prefer the old faithful analog futaba 9402 on my throttle

Still using my SX112 std servo for my throttle. No problems so far.

For me it is so simple ... SX112 for the throttle/brake and 9402 for the steering. I run one way, there is no issue of braking hard and burning my servo out! Hahaha ... but seriuosly, I need to get rid of the SX112 ... want to use rubber band for fail safe and the SX112 is not a happy bunny with the extra strain. Probably use my 9402 for throttle and then get a new servo for my steering. No matter what I still love my MX3, despite the menu always going nuts when you are on NICADS.

Guys. When i got into this hobby, i got myself a M8 with 2 VB servos.
I am still using both this servo on my steering and my throttle linkage.
Is there any problem tat will arrise like the problem sonep is facing now???

The VB servos are high torque (13 kg) analog type servos. They can witstand a lot of beating as analog servos generally tend to not be as sensitive as digital servos. While not having the accuracy, speed and centering capabilities of digital servos, the VB servos are still fine to use in the car.

That is why I still say that getting a good radio gear and servos are an investment. It will see you through to good and bad times !

pls dont argue

different servo will suit different people & their driving style.

it's a matter of preference.

how long was it???? perhaps, it's a good time to double check it now???

Er, double check what? servo?

You typically use it until it kaputs .. then you establish the Mean Time To Failure yourself

Seriously, as far as I know, there's no way to check except to keep it dry, clean & healthy (meaning - no binding, no excessive throw, reduced vibration).

There are many things that can fail in the servo, the circuit, the potentiometer, gears stripped, etc ..

A happy servo = a happy driver

Ummm, trying to throw in some statistical jargons?

Yeah, I agree with you that servos failing can be a somewhat of a stroke of luck or unforced error when somebody hits you exactly where you should not be hit !!.