Need help I have HPI savage x. I'm learning a lot but I'm trying to learn more and see whats going on. I know I bought it used. And It will start but.

[HPI savage x knowledge]

Can anyone tell me what size engine I have and also what I can do to solve my little problems??
Okay so what problems I'm having right now is #1 is the grub screw came out to the rear drive shaft (made my 4 wheel drive go out) which I did some researching and its saying that's the reason why . And #2 my main concerning is why when I start my nitro truck the wheels start spinning by itself and when I hit the brakes it shuts off??

 

[ohsnap]

That looks like an Axial symbol on the head.
I don't know whether you have upgrades in mind or not, but the first thing that I would do other than to get it running and having some fun, would be to get rid of that pipe.

Your wheels spinning shows that the revs are too high and engaging the clutch.
Hitting the brake pits the brakes versus the engine and with the clutch engaged, shuts down the engine.
Your idle point could be too high.
Your idle point could also be too low, and your throttle servo trim and linkages could off enough to produce the revs.

I'm sure this topic has been discussed many a time on this site and I doubt there isn't a sticky on this subject.
Conduct some site searches or maybe someone like Horatio will point the way.

 

[HPI savage x knowledge]

That looks like an Axial symbol on the head.
I don't know whether you have upgrades in mind or not, but the first thing that I would do other than to get it running and having some fun, would be to get rid of that pipe.

Your wheels spinning shows that the revs are too high and engaging the clutch.
Hitting the brake pits the brakes versus the engine and with the clutch engaged, shuts down the engine.
Your idle point could be too high.
Your idle point could also be too low, and your throttle servo trim and linkages could off enough to produce the revs.

I'm sure this topic has been discussed many a time on this site and I doubt there isn't a sticky on this subject.
Conduct some site searches or maybe someone like Horatio will point the way.

Is axial a good motor ?

 

[ohsnap]

Grub screw:
Your assessment sounds good.
Look the part up - find its size and buy a couple grubs - and some blue strength (Locktite) thread-lock.

They are easily obtained - sometimes at your local hardware store - so you don't have to strictly buy HPI.
I have a small canister full of various sizes and shapes.
Start your collection now - you'll find that you will both accumulate and need them.

Do you have the manual?
If not, HPI's website has downloads.

 

[ohsnap]

Axial - I've never owned one, nor seen one in action.
They are probably at least as good as factory engines.
I just noticed an Axial .28 for sale on eBay and from what I could see of that engine and yours, they both look very similar to HPI's Nitro Star K4.6 HO engine - which I believe is a rebadged Kingtair.

Your engine at least starts up and let's assume it has adequate compression.
Your life starts to get good once you get it to idle right.

Once you reach that point, drive it (or at least try).
Then dream of upgrades.
Dumping that pipe is where I started.
Also, a failsafe, especially if you have an old AM transmitter.

 

[HPI savage x knowledge]

That looks like an Axial symbol on the head.
I don't know whether you have upgrades in mind or not, but the first thing that I would do other than to get it running and having some fun, would be to get rid of that pipe.

Your wheels spinning shows that the revs are too high and engaging the clutch.
Hitting the brake pits the brakes versus the engine and with the clutch engaged, shuts down the engine.
Your idle point could be too high.
Your idle point could also be too low, and your throttle servo trim and linkages could off enough to produce the revs.

I'm sure this topic has been discussed many a time on this site and I doubt there isn't a

That looks like an Axial symbol on the head.
I don't know whether you have upgrades in mind or not, but the first thing that I would do other than to get it running and having some fun, would be to get rid of that pipe.

Your wheels spinning shows that the revs are too high and engaging the clutch.
Hitting the brake pits the brakes versus the engine and with the clutch engaged, shuts down the engine.
Your idle point could be too high.
Your idle point could also be too low, and your throttle servo trim and linkages could off enough to produce the revs.

I'm sure this topic has been discussed many a time on this site and I doubt there isn't a sticky on this subject.

Axial - I've never owned one, nor seen one in action.
They are probably at least as good as factory engines.
I just noticed an Axial .28 for sale on eBay and from what I could see of that engine and yours, they both look very similar to HPI's Nitro Star K4.6 HO engine - which I believe is a rebadged Kingtair.

Your engine at least starts up and let's assume it has adequate compression.
Your life starts to get good once you get it to idle right.

Once you reach that point, drive it (or at least try).
Then dream of upgrades.
Dumping that pipe is where I started.
Also, a failsafe, especially if you have an old AM transmitter.

Yes it has good compression still. So that's good. Thank you! I'm very appreciated! So soon as my grub screw gets here around the 27th of this month. I'll get that put in with some blue loctite stuff. And then I'ma try and get my savage too idle or rev a little lower or something because I know these wheels shouldn't be spinning soon as I fire it up or even try turning it over with the roto start

 

[ohsnap]

"I know these wheels shouldn't be spinning soon as I fire it up or even try turning it over with the roto start"

Check your clutch / clutch shoes. Something is wrong if simply turning the engine over with a rotostart spins your wheels.
It is possible that this could be the root cause to your situation.
The clutch bell should freely spin, and the clutch shoes should not be engaged at rotostart speeds (or before you even try to start the engine).

A broken clutch shoe spring or some debris inside the clutch bell could be your problem.

 

[HPI savage x knowledge]

So now I ran into another problem...! My HPI savage x nitro engine, I somehow managed to lose the mid idle screw. The one that's on the side of the carburetor... Has this happened to anyone!? And how do I avoid this next time, I have the new mid screw on the way it'll be here in a few days

 

[ohsnap]

Happened to me.
Older o-rings dry up and shrink.
They provide both an air seal as well as a snugness/friction factor that keeps the needle and its setting in place.
I had a mid-range needle vibrate loose while driving a truggy around a course - no luck in finding it.

Make sure the o-rings on your replacement needle are still in useable condition.
The o-rings on my replacement needle came pre-shrunk and had to be replaced.

I can't think of any better way to describe it at the moment, but if the needle doesn't fight you (does not offer snugness) as you screw it in, replace the o-rings. Otherwise, you are very liable to end up in the same position again.

A buddy and I watched his engines HSN unscrew itself before our eyes as he revved it on the box.
Can't keep a setting that way, but at least he didn't lose it.
He had to order one, but a new o-ring put him back in business.

 

[HPI savage x knowledge]

Happened to me.
Older o-rings dry up and shrink.
They provide both an air seal as well as a snugness/friction factor that keeps the needle and its setting in place.
I had a mid-range needle vibrate loose while driving a truggy around a course - no luck in finding it.

Make sure the o-rings on your replacement needle are still in useable condition.
The o-rings on my replacement needle came pre-shrunk and had to be replaced.

I can't think of any better way to describe it at the moment, but if the needle doesn't fight you (does not offer snugness) as you screw it in, replace the o-rings. Otherwise, you are very liable to end up in the same position again.

A buddy and I watched his engines HSN unscrew itself before our eyes as he revved it on the box.
Can't keep a setting that way, but at least he didn't lose it.
He had to order one, but a new o-ring put him back in business.

Okay thank you so much. I noticed when that happened there was a tiny bit of fuel tryna leak between the carb and the engine... 🤨 Which I think it was doing that because the mid screw needle was missing so it wasnt able to control the fuel and air ratio or something like that... I hope my thoughts are accurate because I don't know any other reason why it would be try leak a tiny bit right there it only makes sense if that's case.🙏

 

[ohsnap]

"I noticed when that happened there was a tiny bit of fuel tryna leak between the carb and the engine... 🤨 Which I think it was doing that because the mid screw needle was missing"

I recall more than a tiny bit of fuel spitting out of mine.
Your observation and instincts are spot on.