Revo 3.3, WTH is wrong with this thing?

[Spookybrittany]

Hey guys,

Let's just start off by saying I'm a newbie to the max, my new-to-me Traxxas Revo 3.3 is my first (running, barely) RC truck. My boyfriend is super into RCs, and he has all sorts of electric ones. This is the only Nitro we have, because his last one ran away into a wall and blew up to say the least.

My Revo has been having hissy fits from the get-go. First, it wouldn't start at all. Fixed that with new batteries, and a new ez start. Got to run it for maybe 30 minutes, amazingly, and the exhaust broke... Fixed that, along with a broken motor mount that I found (yes it is used, probably an og revo from 2009?).

So basically the biggest issue I have, is this thing will NOT stay tuned. I'll get it tuned and going, it'll be amazing... a few full throttle pulls, it seems like the HSN moves, it completely untunes itself and tries to runaway.

We have no problems starting this thing up and it idling, although I do think it idles too high... but I don't know for sure.

It just constantly wants to run away and take off on me... Any suggestions would help, I have been eye balling these forums for months now and its helped a lot so far... I figured screw it, I'm gonna sign up and try to get some direct help to my issue with it.

I have put a new slipper clutch in it, new clutch pads, new fuel lines, air filters, new exhaust, new glowplugs and new official "Top Fuel 33%"

I don't want to prove my boyfriend right and give up on this thing because it's "too much of a headache", so please help me prove him wrong.

 

[Basher_around_town]

If the engine is new, it has to go thru a break-in period, make sure all the bolts are tight as much as you can, make sure all exhaust mounts are secure, and maybe send pictures of where the weak points are. I own a T-Maxx for a year, and I know some weak spots of Traxxas nitros.

 

[Basher_around_town]

Hey guys,

Let's just start off by saying I'm a newbie to the max, my new-to-me Traxxas Revo 3.3 is my first (running, barely) RC truck. My boyfriend is super into RCs, and he has all sorts of electric ones. This is the only Nitro we have, because his last one ran away into a wall and blew up to say the least.

My Revo has been having hissy fits from the get-go. First, it wouldn't start at all. Fixed that with new batteries, and a new ez start. Got to run it for maybe 30 minutes, amazingly, and the exhaust broke... Fixed that, along with a broken motor mount that I found (yes it is used, probably an og revo from 2009?).

So basically the biggest issue I have, is this thing will NOT stay tuned. I'll get it going, it'll be amazing... a few full throttle pulls, it seems like the HSN moves and it completely untunes itself all and tries to runaway.

We have no problems starting this thing up and it idling, although I do think it idles too high... but that's just my mechanics background, and I don't know anything about these except for they're loud, stinky and fast as heck lol.

It just constantly wants to run away and take off on me. I'm terrified to run it anywhere, but my backyard in case it takes off on me and I watch this little truck I adore explode lol

Any suggestions would help, I have been eye balling these forums for months now and you all have helped so much with this thing already.. I figured screw it, I'm gonna sign up and try to get some direct help to my issue with it.

I have put a new slipper clutch in it, new clutch pads, new fuel lines, air filters, new exhaust, new glowplugs and new official "Top Fuel 33%"

I don't want to prove my boyfriend right and give up on this thing because it's "too much of a headache", so please help me prove him wrong.

now that I read the whole thing, never use Traxxas fuel, if you don't do the after-run oil on your filter, it could rust over time since nitromethane is known to pull moisture, and don't run on 33%, it's like running a 3s battery on a car for a beginner, always run nitro on 20% (2s) it's a safe way to run a nitro, and I recommend the VP Racing fuel 20% 9% oil, you can leave the fuel in the tank since it protects from rust and doesn't need after run oil, plus it's a good fuel in general to use. if the engine is new, use 20% and don't go full throttle, let it run slow for a few tanks, about 50% throttle, once the engine starts to sound like its revving higher, its broken in, a good way to test if it's broken in is to spin the flywheel with your finger and see if you can move and makes a pop, if you can not move the flywheel, needs to run a few more tanks at 50% throttle. once she's run in, she's a beast. ask any questions if you need to.

 

[gandalfnz]

Hey guys,

Let's just start off by saying I'm a newbie to the max, my new-to-me Traxxas Revo 3.3 is my first (running, barely) RC truck. My boyfriend is super into RCs, and he has all sorts of electric ones. This is the only Nitro we have, because his last one ran away into a wall and blew up to say the least.

My Revo has been having hissy fits from the get-go. First, it wouldn't start at all. Fixed that with new batteries, and a new ez start. Got to run it for maybe 30 minutes, amazingly, and the exhaust broke... Fixed that, along with a broken motor mount that I found (yes it is used, probably an og revo from 2009?).

So basically the biggest issue I have, is this thing will NOT stay tuned. I'll get it tuned and going, it'll be amazing... a few full throttle pulls, it seems like the HSN moves, it completely untunes itself and tries to runaway.

We have no problems starting this thing up and it idling, although I do think it idles too high... but I don't know for sure.

It just constantly wants to run away and take off on me... Any suggestions would help, I have been eye balling these forums for months now and its helped a lot so far... I figured screw it, I'm gonna sign up and try to get some direct help to my issue with it.

I have put a new slipper clutch in it, new clutch pads, new fuel lines, air filters, new exhaust, new glowplugs and new official "Top Fuel 33%"

I don't want to prove my boyfriend right and give up on this thing because it's "too much of a headache", so please help me prove him wrong.

A properly tuned truck will not want to take off on you.
Are you sure its not your tuning (lean).
Did you tune the truck when its tank is half full?
Dont worry too much about high idle, traxxas plastic carbs are not that good, and its almost impossible to get it to idle low, unless you richen the LSN too much.
When you changed the clutch pads, did you also change the spring?
When it does want to run away, if you richen the HSN does it calm down?

 

[Bogda89]

Hey guys,

Let's just start off by saying I'm a newbie to the max, my new-to-me Traxxas Revo 3.3 is my first (running, barely) RC truck. My boyfriend is super into RCs, and he has all sorts of electric ones. This is the only Nitro we have, because his last one ran away into a wall and blew up to say the least.

My Revo has been having hissy fits from the get-go. First, it wouldn't start at all. Fixed that with new batteries, and a new ez start. Got to run it for maybe 30 minutes, amazingly, and the exhaust broke... Fixed that, along with a broken motor mount that I found (yes it is used, probably an og revo from 2009?).

So basically the biggest issue I have, is this thing will NOT stay tuned. I'll get it tuned and going, it'll be amazing... a few full throttle pulls, it seems like the HSN moves, it completely untunes itself and tries to runaway.

We have no problems starting this thing up and it idling, although I do think it idles too high... but I don't know for sure.

It just constantly wants to run away and take off on me... Any suggestions would help, I have been eye balling these forums for months now and its helped a lot so far... I figured screw it, I'm gonna sign up and try to get some direct help to my issue with it.

I have put a new slipper clutch in it, new clutch pads, new fuel lines, air filters, new exhaust, new glowplugs and new official "Top Fuel 33%"

I don't want to prove my boyfriend right and give up on this thing because it's "too much of a headache", so please help me prove him wrong.

It sounds like it has multiple issues.

First I will never recommend for anyone to buy used Nitro rc as a first nitro.

Second, it sounds like clutch spring is weak. And it catches at lower rpm. New clutch and spring is 7.29 part number TRA4146.

Second, I would highly recommend 20 percent nitro, my favorite is sidewinder but you can run anything available in you local hobby shop.

Third, it sounds like it's lean on the bottom and high idle gap. When you tune nitro engine you should tune it warm, if you tune it cold it will lean out when gets warm. If you post a video it will be easier to diagnose.

If y live in Chicago area by any chance I can help you tune it and fix it

 

[STONER RC]

Hey guys,

Let's just start off by saying I'm a newbie to the max, my new-to-me Traxxas Revo 3.3 is my first (running, barely) RC truck. My boyfriend is super into RCs, and he has all sorts of electric ones. This is the only Nitro we have, because his last one ran away into a wall and blew up to say the least.

My Revo has been having hissy fits from the get-go. First, it wouldn't start at all. Fixed that with new batteries, and a new ez start. Got to run it for maybe 30 minutes, amazingly, and the exhaust broke... Fixed that, along with a broken motor mount that I found (yes it is used, probably an og revo from 2009?).

So basically the biggest issue I have, is this thing will NOT stay tuned. I'll get it tuned and going, it'll be amazing... a few full throttle pulls, it seems like the HSN moves, it completely untunes itself and tries to runaway.

We have no problems starting this thing up and it idling, although I do think it idles too high... but I don't know for sure.

It just constantly wants to run away and take off on me... Any suggestions would help, I have been eye balling these forums for months now and its helped a lot so far... I figured screw it, I'm gonna sign up and try to get some direct help to my issue with it.

I have put a new slipper clutch in it, new clutch pads, new fuel lines, air filters, new exhaust, new glowplugs and new official "Top Fuel 33%"

I don't want to prove my boyfriend right and give up on this thing because it's "too much of a headache", so please help me prove him wrong.

Welcome to the forum. The problem is most likely the fuel your running. Top fuel is a very high oil %. I only use top fuel for break ins. It makes the truck seem like it runs lean. Witch makes for some pain in. The as* tuning.
Need to get a good fuel. I run bone brew 30/10. Or O'DONNELL fuel. With a 10% oil amd 30% nitro. I would start with that.

It sounds like it has multiple issues.

First I will never recommend for anyone to buy used Nitro rc as a first nitro.

Second, it sounds like clutch spring is weak. And it catches at lower rpm. New clutch and spring is 7.29 part number TRA4146.

Second, I would highly recommend 20 percent nitro, my favorite is sidewinder but you can run anything available in you local hobby shop.

Third, it sounds like it's lean on the bottom and high idle gap. When you tune nitro engine you should tune it warm, if you tune it cold it will lean out when gets warm. If you post a video it will be easier to diagnose.

If y live in Chicago area by any chance I can help you tune it and fix it

Traxxas nitros are temperamental. It's not the utch spring. I have had the Tmaxx 2.5 original and the Tmaxx 3.3. Both jump foward at idol always have. It's the crap top fuel they say to run . It's has a 15% or higher oil %. Witch for those nitros is way to high. It should be between 9-12% oil. I only use top fuel for the first break in. Witch at this point should be way past that. She just needs to change fuel and shouldn't have a problem tuning any more...

And definitely don't want to start the engine with out it being warmed up. With a heat gun or a nitro head warmer. Those are about 30$ and well worth it. Cold starts are so bad for a engine

 

[Greywolf74]

I would read through THIS thread and use the nitro engine tuning flow chart after setting the LSN and HSN back to factory defaults.

The only things I can think of that would make it run away on you would be:

1) Loss of signal between the receiver and transmitter. There may be a damaged antenna on the receiver or some other fault causing a loss of connectivity. Make sure the "fail-safe" feature is set on your receiver. If this is the issue then the fail-safe will keep it from running away.

2) Something is causing the throttle servo to get stuck at high throttle and therefore "runs away"

It wouldnt hurt to look at the clutch shoes and springs just to make sure theyre in decent condition but usually when thats an issue it will try to run away from you as soon as you start it up so I dont think thats it.

If you could get some video of it doing what its doing and posted on here that may help us pinpoint the problem area.

I do agree that the Traxxas fuel is no good. I dont think it matters if you run 20% or 30% just dont switch back and forth or else you'll have to re-tune every time you switch. Find some fuel that has 8%-12% oil content in it and that should be good. A lot of the guys on here use Bones brew or O'Donnell's but anything in that oil% range should be fine.

Nitros definitely have a higher learning curve than electrics but theres something very satisfying about them once you get a feel for it. At least if you like the sound and smell of burning nitro and you like to tinker. A lot of people arent in to it that kind of stuff or just want simple plug and play and thats one of the reasons electrics have become so popular. Nitro is an artform and if you stick with it you'll learn it eventually and you'll appreciate it that much more.

Hope this helps

 

[Spookybrittany]

A properly tuned truck will not want to take off on you.
Are you sure its not your tuning (lean).
Did you tune the truck when its tank is half full?
Dont worry too much about high idle, traxxas plastic carbs are not that good, and its almost impossible to get it to idle low, unless you richen the LSN too much.
When you changed the clutch pads, did you also change the spring?
When it does want to run away, if you richen the HSN does it calm down?

I have replaced the clutch pads and spring with the 4146X (for higher stall).

My boyfriend has been doing the tuning when it gets temperamental (he had a T-Maxx 3.3) and he says it does for a few seconds, then just looses it and goes full throttle. We have been tuning it cold, maybe I will try and let it warm up first before tuning it today. I'll take pictures and a video.

now that I read the whole thing, never use Traxxas fuel, if you don't do the after-run oil on your filter, it could rust over time since nitromethane is known to pull moisture, and don't run on 33%, it's like running a 3s battery on a car for a beginner, always run nitro on 20% (2s) it's a safe way to run a nitro, and I recommend the VP Racing fuel 20% 9% oil, you can leave the fuel in the tank since it protects from rust and doesn't need after run oil, plus it's a good fuel in general to use. if the engine is new, use 20% and don't go full throttle, let it run slow for a few tanks, about 50% throttle, once the engine starts to sound like its revving higher, its broken in, a good way to test if it's broken in is to spin the flywheel with your finger and see if you can move and makes a pop, if you can not move the flywheel, needs to run a few more tanks at 50% throttle. once she's run in, she's a beast. ask any questions if you need to.

I believe it is fully broken in, it has about 8 hours of drive time on it and then buddy sat it on a shelf as a paper weight for x amount of years. We were both fricking shocked it even runs still, at all. These slight hissy fits, are definitely better than the seized engine I worried it having

 

[Greywolf74]

I have replaced the clutch pads and spring with the 4146X (for higher stall).

My boyfriend has been doing the tuning when it gets temperamental (he had a T-Maxx 3.3) and he says it does for a few seconds, then just looses it and goes full throttle. We have been tuning it cold, maybe I will try and let it warm up first before tuning it today. I'll take pictures and a video.

I believe it is fully broken in, it has about 8 hours of drive time on it and then buddy sat it on a shelf as a paper weight for x amount of years. We were both fricking shocked it even runs still, at all. These slight hissy fits, are definitely better than the seized engine I worried it having

If you havent already I would tear the engine down, clean it and when you put it back together I would seal the engine and carb against air leaks.

 

[Spookybrittany]

I would read through THIS thread and use the nitro engine tuning flow chart after setting the LSN and HSN back to factory defaults.

The only things I can think of that would make it run away on you would be:

1) Loss of signal between the receiver and transmitter. There may be a damaged antenna on the receiver or some other fault causing a loss of connectivity. Make sure the "fail-safe" feature is set on your receiver. If this is the issue then the fail-safe will keep it from running away.

2) Something is causing the throttle servo to get stuck at high throttle and therefore "runs away"

It wouldnt hurt to look at the clutch shoes and springs just to make sure theyre in decent condition but usually when thats an issue it will try to run away from you as soon as you start it up so I dont think thats it.

If you could get some video of it doing what its doing and posted on here that may help us pinpoint the problem area.

I do agree that the Traxxas fuel is no good. I dont think it matters if you run 20% or 30% just dont switch back and forth or else you'll have to re-tune every time you switch. Find some fuel that has 8%-12% oil content in it and that should be good. A lot of the guys on here use Bones brew or O'Donnell's but anything in that oil% range should be fine.

Nitros definitely have a higher learning curve than electrics but theres something very satisfying about them once you get a feel for it. At least if you like the sound and smell of burning nitro and you like to tinker. A lot of people arent in to it that kind of stuff or just want simple plug and play and thats one of the reasons electrics have become so popular. Nitro is an artform and if you stick with it you'll learn it eventually and you'll appreciate it that much more.

Hope this helps

So much information, glad I signed up on here! I really appreciate it

As soon as my boyfriend introduced me to what a nitro rc truck was, I looked at him and I was like "I WANT ONE." Even with its problems, the few minutes I get to drive it before problems come up, nothing beats that feeling haha

 

[Spookybrittany]

If you havent already I would tear the engine down, clean it and when you put it back together I would seal the engine and carb against air leaks.

Could it possibly be the carb being old and the needles being damaged/worn out? I was thinking that, and maybe I'll just get a new carb?

 

[Greywolf74]

Could it possibly be the carb being old and the needles being damaged/worn out? I was thinking that, and maybe I'll just get a new carb?

An air leak can cause the RPMs to spin up on the engine but before I looked at any of that Id address the other 2 possibilities in my earlier post first and rule those out as those are the 2 most likely culprits I can think of for a "run away"

I doubt theres anything wrong with the carb other than maybe an airleak

 

[Spookybrittany]

Here's the quick snap I got of us starting it up yesterday after replacing the fuel lines and clutch pads/springs, I'll get a longer video today of it starting and idling.
And nevermind my naïve excitement, but here's the few pulls I got last night before it tried to runaway.

 

[Bogda89]

Here's the quick snap I got of us starting it up yesterday after replacing the fuel lines and clutch pads/springs, I'll get a longer video today of it starting and idling.
And nevermind my naïve excitement, but here's the few pulls I got last night before it tried to runaway.

Please don't run with no body, you can damage parts when flip over, in extreme cases even break the engine

 

[STONER RC]

I would definitely get new carb and new fuel. The. You should set. Sounds good other wise. Top fuel is crap sorry to say. Way to much oil in it. And it does tmatter what %nitro you run there really isn’t much of a difference. But like WOLF said you would need to re tune every switch. I run 30/10 in all my nitros from buggy to Tmaxx 3.3 amd 2.5

Please don't run with no body, you can damage parts when flip over, in extreme cases even break the engine

Some time you need to run with out body while tuning. It's a pain in the as*. To take body off all the time. She want bashing or anything crazy. I run with out bodies all the time. Can't drive like a jackwagon when top less

 

[Greywolf74]

I would definitely get new carb and new fuel. The. You should set. Sounds good other wise. Top fuel is crap sorry to say. Way to much oil in it. And it does tmatter what %nitro you run there really isn’t much of a difference. But like WOLF said you would need to re tune every switch. I run 30/10 in all my nitros from buggy to Tmaxx 3.3 amd 2.5

Some time you need to run with out body while tuning. It's a pain in the as*. To take body off all the time. She want bashing or anything crazy. I run with out bodies all the time. Can't drive like a jackwagon when top less

When my wife is topless I definitely drive like a jackwagon

 

[Spookybrittany]

I would definitely get new carb and new fuel. The. You should set. Sounds good other wise. Top fuel is crap sorry to say. Way to much oil in it. And it does tmatter what %nitro you run there really isn’t much of a difference. But like WOLF said you would need to re tune every switch. I run 30/10 in all my nitros from buggy to Tmaxx 3.3 amd 2.5

Some time you need to run with out body while tuning. It's a pain in the as*. To take body off all the time. She want bashing or anything crazy. I run with out bodies all the time. Can't drive like a jackwagon when top less

Literally did a few rips down the alley after tuning for different fuel. It's not like I took it into a bush with no body.

I love that it does sound good otherwise, so maybe a new carb and lower oil % fuel will do a wonder for it.
I ran it the first time with 20/12 I believe, I have a few videos of that too I can upload, before all the parts were replaced on it. (Clutch pads, spring, motor mount, fuel lines, exhaust etc). This is where the exhaust broke too lol

 

[gandalfnz]

I just remembered I used to have the same prob with runaway on my Revo 3.3 which I have sold eventually.

Does your Revo come with an OPTIDRIVE? Its a little box, looks like a receiver and is in charge of making sure you dont shift into reverse by accident, while still moving forward and end up damaging the gearbox.

Once I had removed the optidrive (you can run without it), I had no more issues.
Try this, is quick and easy to do, rather than start throwing money at it.

These optridrives are nothing but trouble, and since your throttle servo plugs directly into it, could be the reason why its flooring it.

 

[Spookybrittany]

And here's just right now, the starter battery died on us lol

I just remembered I used to have the same prob with runaway on my Revo 3.3 which I have sold eventually.

Does your Revo come with an OPTIDRIVE? Its a little box, looks like a receiver and is in charge of making sure you dont shift into reverse by accident, while still moving forward and end up damaging the gearbox.

Once I had removed the optidrive (you can run without it), I had no more issues.
Try this, is quick and easy to do, rather than start throwing money at it.

These optridrives are nothing but trouble, and since your throttle servo plugs directly into it, could be the reason why its flooring it.

I'm gonna be trying it out a few more times with tuning, and if nothing works, I'm gonna try this next.

 

[Bogda89]

Literally did a few rips down the alley after tuning for different fuel. It's not like I took it into a bush with no body.

I love that it does sound good otherwise, so maybe a new carb and lower oil % fuel will do a wonder for it.
I ran it the first time with 20/12 I believe, I have a few videos of that too I can upload, before all the parts were replaced on it. (Clutch pads, spring, motor mount, fuel lines, exhaust etc). This is where the exhaust broke too lol

It runs nice, I would lower the idle a little bit, and maybe go richer on a high speed needle one or two hours. Be careful when running on grass, it's a lot of resistance and engine can overheat