HPI Savage X 4.6 unstoppably spinning wheels at IDLE

[Oli129]

Dear Everyone!

I am a newbie to these forums but not that beginner to the nitro R/C world. I found a topic somewhere a week ago here disscussing such an issue I post here about. However, I have failed finding out what is wrong with my toys.

I own an HPI Savage X 4.6 and a Trophy 4.6 (same engine as on the Savage but the V2) as well. I bought the first in 2012 and the latter last year. A week ago I had to disassemble both. My Savage had a worn clutch issue and a broken pressure spring in the engine, the Trophy simply had too much so I had to replace the rear engine ball bearing. I neither touched the piston nor the sleeve on both, they look just super fine and work as they should.

Note that this is the first time I ever disassembled their engines. So I reassembled, sealed them and they just run quite fine.
BUT, they both engage the clutch at IDLE no matter what I do to them and their wheels keep spinning like crazy all the time.
What I did: Checked the proper clutch position, springs, spacers, washers, bearings, bells. None of them are tight or anything, bells move super freely.
Set all the needles to their default "factory flush" positions. Tried to play with the idle needle, however what I can achive is to either give the engine more throttle or to have it cut off. But the wheels just keep spinning.
I can however block them with the brake or with my hands, but on releasing...start spinning again.

I have spent quite a nice time trying to find out how to solve this, but I am still unsuccesfull.

Could anyone please give me some advice what I should check on the engine or what I am missing?!
These engines look quite simple to me and still...

Any help would be greatly appreciated! Thank you very much!

Oliver

 

[Jam Racing 1]

does this happen when the truck is on the ground or just while on a stand......

 

[Oli129]

Ohh yes, I am sorry! Forgot to let you know that this happens on a stand off ground! I did not want to burn the clutch shoes. And so far I remember after breaking in for the first time years ago at the second tank the tires stopped spinning at idle.

 

[Jam Racing 1]

I would put them on the ground so as to have the friction of something to keep the wheels from spinning, if I start mine on a stand the wheels also spin, but stops soon as I put them on the ground, and I have not burnt a clutch as yet.....

 

[Oli129]

Hmm, okay I try that too, I was just concerned burning down the brand new clutch shoes. And like I said I remember them not spinning off ground when idling at least not this crazy fast.

 

[rcnut14]

mine spin a good bit too. ur clutch shoes might wear a little, but very slightly. u certainly won't burn them out.

 

[Oli129]

mine spin a good bit too. ur clutch shoes might wear a little, but very slightly. u certainly won't burn them out.

Okay thank you! Well I have placed the Savage on the ground, started it and looks fine, however lifting it up and starts crazy spinning again. But I guess then it is just okay.

Trophy is different though. Putting down and it starts running by itself... I wonder what I am doing wrong.

 

[rcnut14]

did u ajust the idle on the trophy? did u trim the throttle servo?

 

[Oli129]

did u ajust the idle on the trophy? did u trim the throttle servo?

Yes I did adjust the idle needle to a point where the engine would just stop if it had less RPM. Anyways the same applies to the Savage though that does stay stationary.
Also I have adjusted the throttle needle so that it is in closed position. One other thing I noticed is that the engine can get fuel with the pressure line off of the exhaust!

Thank you very much!

 

[rcnut14]

try adjusting the throttle servo on ur remote. that affects the idle as well.

 

[Oli129]

try adjusting the throttle servo on ur remote. that affects the idle as well.

Ohh sorry I meant throttle servo, and yes it is in neutral position, so it is not affecting the carb at all!

 

[rcnut14]

actually, it can affect the carb. u have to trim it, just like u have to trim the steering.
take ur air filter off. at neutral, the should be a 1mm gap between the carb body and the little thing that slides inside the carb. if there's too much gap, u will idle high.

 

[Oli129]

Ok

actually, it can affect the carb. u have to trim it, just like u have to trim the steering.
take ur air filter off. at neutral, the should be a 1mm gap between the carb body and the little thing that slides inside the carb. if there's too much gap, u will idle high.

Okay, that I understand! But I checked the gap as usual, and is not extremely open. However I cannot keep the 1mm because it bogs soon and cuts off! It is more like 2,5-3mm wide to keep it running with everything else set flush...

 

[Jam Racing 1]

Then it is more likely your high and low mixture needles being off. try going back to breakin settings and start over again.....
should only be a 1mm or so gap on the slide at idle setting.....

 

[Oli129]

Then it is more likely your high and low mixture needles being off. try going back to breakin settings and start over again.....
should only be a 1mm or so gap on the slide at idle setting.....

Alright, then I start all over again. One more thing, how is it possible that the engine can suck the fuel up without the pressure line?! Thank you very much!

 

[rcnut14]

it can't. ive accidentally done it, and it makes the truck run really weird for a few seconds than it dies.

 

[Oli129]

it can't. ive accidentally done it, and it makes the truck run really weird for a few seconds than it dies.

Awesome :'D it sucks the fuel no matter what! Maybe the Venturi effect takes place. Whatever...
But this F4.6 engine drives me nuts, still engages the clutch and the wheels start turning crazy. Could it happen that it has an air leak somewhere and this way it revs higher than normal so that no idle needle could ever control that?!

 

[rcnut14]

no, probably not

could u take a vid so we can hear the engine?

 

[Oli129]

no, probably not

could u take a vid so we can hear the engine?

Absolutely, will do that!

Thank you!

 

[Oli129]

It seems I was able to solve it! The clutch spring was way too weak, so that it engaged! I guess once it could have overheated thus making it more stretched! Now that I have shortened the spring everything looks fine again!
Thank you very much for your support!

 

[Jonesy123]

Hi all I'm new to this and I have recently brought a savage on eBay I'm looking for advise on my problem I've spent a lot of time trying to work it out but can't seem to figure it out.
I've trimmed my remote, changed the glow plug, set the carb back to factory settings and still nothing!
Every time I start my truck up it's on full throttle all the time I press the brake on the remote and it just about stops the wheels but if I hold the brake for to long it just cuts out and if I just touch the throttle it cuts out.
If anyone could help me I would be very greatfull
Thanks

 

[Jam Racing 1]

Hi all I'm new to this and I have recently brought a savage on eBay I'm looking for advise on my problem I've spent a lot of time trying to work it out but can't seem to figure it out.
I've trimmed my remote, changed the glow plug, set the carb back to factory settings and still nothing!
Every time I start my truck up it's on full throttle all the time I press the brake on the remote and it just about stops the wheels but if I hold the brake for to long it just cuts out and if I just touch the throttle it cuts out.
If anyone could help me I would be very greatfull
Thanks

https://www.hpisavageforum.com/threads/the-complete-beginners-guide-to-rcs.814/

You should read thru that thread before going much further

 

[GAJ]

It can only rev high if it can get the air to do so. Make sure idle gap is about 1mm and that the slid always goes back to the idle stop. If you are reving high at the 1 mm idle gap, you are most likely sucking air from somewhere else.