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New Savage X 4.6 Owner with some questions

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M

M Shark

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McAllen TX
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First and foremost, this is my first RC car ever. I am a total noob with RC cars but I have been turning wrenches on real cars for years.

I have a Savage X 4.6 that I just started the break in process. I have used a total of 6 tanks so far for the break in. 2 Tanks for the warm up, 2 tanks for the first run, 1 tank for the 2nd run and so far 1 tank used during the tuning process.

Everything seemed to go well until I hit the throttle a little and saw debris flying off from the truck.

I immediately checked it out and the first thing I noticed was that the spur gear was completely off the transmission. The teeth of the spur gear did not seem worn out but the back of the spur gear looked burnt. The slipper pad was missing about half a piece, looked black and appeared to have melted onto the back of the spur gear.

Any ideas what might have happened?

For your info, I use 30% Nitro fuel. I also had a hard time starting the truck initially so I leaned out the HSN maybe about (3 ) 1/8 turns and increased the idle about 1/2 turn coz the truck would die on me and conk out when idling.

My questions:

1. What caused the meltdown?
2. Should I upgrade the spur gear?
3. Any other comments and advice much appreciated.

Thanks in advance! From a noob!

---------- Post added at 10:30 PM ---------- Previous post was at 10:26 PM ----------

The highest temperature reading I got from an external temperature gauge was about only 215 degrees. Most of the time it ranged from 140-180 degrees.
 
sounds like your slipper was set to loose which would cause the spur to melt. the more it melted the looser the slipper nut got .on a savage lock the slipper then loosen about 1\8th tuen if u still have an issue with a melted spur lock it down. its normal to need to open the gap a little and lean one or both needles to get the truck to run. nitro motors come really rich from factory. 215 is a little low if u where tuning for performace and felt it was broken in good. which on that motor 5 tanks should be good. and btw as long as your gear mesh is set properly and slipper not to loose a spur should last a couple gallons of fuel as long as nothing happens most people do run a metal spur on the savage tho

---------- Post added at 12:03 AM ---------- Previous post was at 12:02 AM ----------

you want your temp to be at least 220 after a couplewot (wide open throttle)passes. tune will be the life of your motor and also the life of your glow plugs
 
Thanks for the reply guys! The idle gap was about 1mm before I even fired the truck up. I had to adjust the throttle linkage a little since the truck would die everytime I turned on the transmitter and reciever (long story).

But the loose slipper pad makes sense. Just before the spur gear gave way, I noticed the truck wasn't getting any faster but it still did not sound to be in optimal performance. I'll make sure it's on right next time and adjust the mesh as best I can. I just ordered 4 spur gears.

Another question. This morning I tried to fire up the engine (without the spur gear in place) just to get rid of the extra fuel in the tank. But the truck would not fire up. Glow plugs were bright orange, igniter is fully charged, about half a tank left.

Now would the engine fire up on it's own without the spur gear to connect to the transmission?

Childress, I was hoping to get higher temps. After every full throttle pass I'll check the temp gauge and adjust the HSN. but the highest I got was 215. I was still in the process of tuning the HSN when the spur gear blew up. :( Hopefully I'll have better luck when I get the replacements.
 
Last edited:
Hey Childress, While waiting for my spur gears to arrive I tried to fire up my engine this morning to burn the extra fuel in the tank but it wouldn't start up. Glow plugs and igniter are fine.

Wouldn't the engine fire up even without the spur gear in place?
 
yea it will start with no spur it just wont move. Take the tank pressure line off the pipe and blow into it yourself to make sure your actually getting fuel into the case if the lsn is to lean it wont let fuel into the carb i had this problem with a used savage i bought. you may have to play with your needles a bit to get it to start and once you get it started go from there. Does the motor still have good compression?
 
How would I do a compression test? I did notice the piston to be a little slightly light copper color as compared to being silver before. Does that mean anything?
 
I checked the compression as explained online and it seems to pass. Anyway, I was able to start her up by quickly covering and opening up the exhaust port while turning the engine with no problems. After that, it started up without any problems.

Can't wait for my replacement parts to come in. Thanks for the help guys!
 
The discoloration of the piston is either after run oil if your using it or the die in the fuel your using. And that is priming the engine you have to do that to start any nitro motor.
 
I just got my spur gear replacements and I got 1 question.

Is it normal for the spur gear to spin a little wobbly? Even with the transmission out, no matter how I adjust the spur gear wether super tight or loose it happens to spin a little wobbly while spinning freely.
 

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