A Throttle Servo Setup problem
 

Thanks for looking & trying to help!

The following video explains the problem:

+ YouTube Video

Defnitely a weak servo saver spring. You really don't need a "servo saver" on the throttle / brake though.

It will require a little creative building, but what you need is to copy the design of a standard 1/8th scale nitro buggy/truggy carb linkage. There is a direct pull on both the carb and brakes, but the pivots allow the servo to rotate in both directions.

With that design, you would use a standard servo horn, which would be more than strong enough to pull the bands (by the way, I use those on my carb too).

Here's a picture of a random buggy I found online. The parts will differ from brand to brand, but the concept is the same for all. It should be clear enough to fabricate something similar for your LST.

Throttle return springs are really just to close the carb if the linkage comes off. With power off your servo just has too much resistance. Ditch the servo saver or get a servo with less resistance with power off.

At about 2:20 in video, do you see how much force was needed to open the carb when you used your fingers (2 bands too much)? Try with the throttle spring and 1 band. But yes, its 100% your servo saver. It there to save your servo from all of that extra pressure.

Clamp more springs onto the servo saver to stiffen the action. Are the two bands torquing the carb barrel to the point that it doesn't want to slide because they are pulling on one side of the barrel ? Reroute the rubber bands around the neck of the carb, instead of having it pull on one side.

Goto lstforums.com, it's the place to go for any LST based question.:D

excellent video.
 

I recommend just not using the bands or the spring, Just keep your batteries charged and you won't have any problems. The servo arm fits so well in the truck I'd hate to change it....Now go drive the truck and get it dirty.....

Servo
 

Ditch the cheap servo and get a coreless motored servo .The force required to pull the servo closed is too much with a cheap non coreless servo.

Thanks for all the replies! I'm heading over to www.lstforums.com and posting this thread there also.

I actually like that idea ... it's the most easiest one for me to do. I don't have to buy any extra parts and such! The time has come for my lst to roar instead of sitting on the repair bench for months and months ...

Thanks a bunch!

I can't agree with that..I still have a hopped up LST2 that I raced for a couple( you'll see it at LST forums..same username as I use here )of years and it's a brute..at 13lbs and 40+mph, it makes for one scary runaway in the event that something does happen or glitch.

You need to order the proper servo horn, because the proper one shouldn't have a built in servo-saver, it should be a solid unit, download the manual, and look at the part number. You're using the wrong one, get the right one and your problem will go away.

what you need is what they put stock on the lst2 and xxl. It doesn't use a servo saver on the throttle/brake servo. They are only about $6 and come with what you need to change it over. The servo you have is fine to use, I use a jr z550 for mine and works just fine on my lst2 racer.

Losi part number LOSB4204

http://www.amainhobbies.com/product_...e-Linkage-LST2

http://c0456141.cdn.cloudfiles.racks...s/losb4204.jpg

Ok, great!

I will get that part (LOSB4204).

So I just put it on there and it should fit smoothly? Nothing I have to do other than fine tuning with the radio after installing? =)

Correct, that servo horn should be splined correctly for a JR or Airtronics servo. This will end your problem. I'm not sure why your truck had a servo saver on the throttle/brake servo, but it doesn't belong there.

For some reason the lst, raminator, and aftershock all came with that set-up. You will need to set your remote epa and adjust the collars on the linkage which is easy to do. That linkage will come with 3 different adaptors make sure you use the one that has a 23 on it for the jr servo. Enjoy

Yep, that will do it....and it will make the geometry just like the 1/8th nitro buggy picture I posted earlier. I'm sure you'll be much happier with this arrangement.

Also, keep those bands on your carb. There are just too many bad things that can happen with a runaway...