RC car fuel - does it go bad?

So I'm happily resurrecting an RC gas truck I got years ago at a yard sale. A HPI Savage 25. It actually runs now, albeit rather poorly. The last time I played with things like these, I was pre-pubescent and it was a tether plane. I'm a little out of practice.

So, a few questions!

The nitro fuel I have is probably at least 6 years old. Does it ever go bad? If I have to buy some, ok. But if I don't, I'd rather be cheap. Any recommendations on fuels and particularly what to watch for and watch out for?

I'm speculating that I need a much hotter glow plug than what it has. When I disconnect the pre-heater, it frequently dies. Of course, this could be related to the old fuel I suppose. As well I suppose to the fact it was in the 40's when I was playing with it. Tell me if you suspect it is an old fuel problem. Any problems with getting a hotter glowplug btw?

The engine is wonky on throttle response. Gentle motion is sorta ok. But snap the throttle open or closed, and it likely will instantly die. Again, bad fuel?

The carburetor trim adjustment is weird. Manual says set the screw flush with the tube it's in. Do that and it will start just fine. Touch the throttle and it dies. Back the screw out a full turn and it won't start, but responds to the throttle much better. Much more prone to 4 stroking too. Fuel again? I'm going to have to buy a fresh jug of Nitro, aren't I?

Is there anything magical I can do to improve the steering servo? It works, but it's weak. The throttle and brake servo seems to do its thing just fine. But steering, that's not so good. In fact, you half steer it with the trim knob.

I'm hoping to get this thing running and useable to give to my son for christmas. He really can't fly the planes in the back yard, but he could have a lot of fun with a truck...if it works. And a gas engine, that's great for getting educational burns with and such. As well learning how to make a touchy engine start and run.

Sage comments and suggestions welcome and sought after.

Step one- junk the steering servo, get a new one. Whatever's in there was probably old the last time it ran, things have changed. A NEW rocksolid Hi-tech will probably set you back 30 bucks.

Step two- I don't have a frickin clue. I started on electric... nitro appealed to me because of sheer speed, but I didn't like the finicky nature, then we got lipos and brushless. I'd bet that my current drift rig would keep up with your average nitro truck if I put actual tires on it. To me it sounds like you've got fuel that's gone to pot and a dead glow plug. Whenever you give it the beans it floods out. I'd say start with new fuel, and move up the price ladder from there.

Ohh man, I was just looking for a HPI Super Nitro Rally RS4 on eBay. Best RC Ive ever owned...

Nitro does go bad. It will separate, it is premix after all. It is also hydroscopic, so that also won't help if it's been sitting for a long time.

New plug, pull the head and carb and hit with carb cleaner. Replace all fuel lines. Should be good to go.

No idea on what servos to recommend nowadays. A Hitec 645MG should be around $30 or so new. Used them in my cars for steering just fine.

It's nitromethane, so yes it will attract moisture and go bad. Get some fresh stuff and a couple new glow plugs from your local shop.

Yes it does. Alcohol sucks up water like mad and since 50-75% of the fuel is alcohol you will be chasing the needle adjustment all over the place and never finding it.

6 months was my rule of thumb when I was racing boats. If the fuel was older than 6 months, replace it.

Here at work (Traxxas) we tell our customers fuel has a 3-6 month shelf life depending upon how it is stored. Anything over that and it's usually bad. Also, definitely sounds like the glow plug needs to be replaced. I'd get fresh fuel and a new plug before you start addressing the other issues you described.

blackzx3_13 wrote: Here at work (Traxxas) we tell our customers fuel has a 3-6 month shelf life depending upon how it is stored. Anything over that and it's usually bad. Also, definitely sounds like the glow plug needs to be replaced. I'd get fresh fuel and a new plug before you start addressing the other issues you described.

Dude, you work at Traxxas? You guys have been knocking stuff out of the park lately.

Picked up a jug of fresh fuel and a new glow plug. And since I walked into my friendly neighborhood hobby shop with the truck in hand, he looked it over and showed me several things, good and not so good.

I do really like having a nice local business to help me out.

Can't play with it today, as the boy is home.

P.S. Is there any use for the old fuel? Seems like a waste just to toss it into some old engine oil and dispose of it.

tuna55 wrote: Dude, you work at Traxxas? You guys have been knocking stuff out of the park lately.

Yeah, I have for going on 5 years. Mostly Customer Service but I've also done some marketing and testing things.

foxtrapper wrote: P.S. Is there any use for the old fuel? Seems like a waste just to toss it into some old engine oil and dispose of it.

Not really any use for it. Know a few guys who have "spiced up" a camp fire with it though.

blackzx3_13 wrote:

tuna55 wrote: Dude, you work at Traxxas? You guys have been knocking stuff out of the park lately.

Yeah, I have for going on 5 years. Mostly Customer Service but I've also done some marketing and testing things.

So hook me up, I'll PM you with a question.

tuna55 wrote:

blackzx3_13 wrote: Here at work (Traxxas) we tell our customers fuel has a 3-6 month shelf life depending upon how it is stored. Anything over that and it's usually bad. Also, definitely sounds like the glow plug needs to be replaced. I'd get fresh fuel and a new plug before you start addressing the other issues you described.

Dude, you work at Traxxas? You guys have been knocking stuff out of the park lately.

I am the jealous. Traxxas is precisely on the opposite side of the country from me. I'd love to work there- I have had many things from them.

mndsm wrote:

tuna55 wrote:

blackzx3_13 wrote: Here at work (Traxxas) we tell our customers fuel has a 3-6 month shelf life depending upon how it is stored. Anything over that and it's usually bad. Also, definitely sounds like the glow plug needs to be replaced. I'd get fresh fuel and a new plug before you start addressing the other issues you described.

Dude, you work at Traxxas? You guys have been knocking stuff out of the park lately.

I am the jealous. Traxxas is precisely on the opposite side of the country from me. I'd love to work there- I have had many things from them.

Exactly this.

You guys need a fantastic mechanical engineer who could both work entirely from home and could provide four kids to bash things to test them?

I can honestly say it's one of the few times I'd go back to customer service!

mndsm wrote: I can honestly say it's one of the few times I'd go back to customer service!

Don't want to thread jack too much, but it is a pretty cool job sometimes. I've been able to do and see some motorsports related things that I though I would never be able to due to our involvement in full size motorsports. At the end of the day though, it is a Customer Service job. You'd be surprised how many people get butt hurt because their toy car doesn't work.

I'd be happy to answer any RC car tech related questions that I can.

You might be the person I want to talk to then. What is the warranty life/what kind of cost am I looking at in getting an ESC replaced? It's an older Traxxas brushless ESC that I have in comination with a VXL motor that I got in a swapped Rustler. I FURTHER swapped the Rustler, now it's an LCG Slash (I'm rather proud of it, given as little as I have into it). I'm not 100% sure what happened, I'm told it might have overheated. No matter what I do to it though, reprogramming or otherwise- it cogs like crazy, and refuses to do reverse no matter what mode it's in. I'm told it's toast. Can you shed any light on it?

mndsm wrote: You might be the person I want to talk to then. What is the warranty life/what kind of cost am I looking at in getting an ESC replaced? It's an older Traxxas brushless ESC that I have in comination with a VXL motor that I got in a swapped Rustler. I FURTHER swapped the Rustler, now it's an LCG Slash (I'm rather proud of it, given as little as I have into it). I'm not 100% sure what happened, I'm told it might have overheated. No matter what I do to it though, reprogramming or otherwise- it cogs like crazy, and refuses to do reverse no matter what mode it's in. I'm told it's toast. Can you shed any light on it?

Is it the one in the project car section with the mini-van body? Cogging + no reverse is a sure sign it's been overheated. Reverse is usually the first thing to go, then the cogging starts. If it's older, the only thing we offer is a discounted replacement plan. You can send us that ESC and we'll sell you a new VXL ESC for $50 plus $5 shipping. We can replace the motor for another $35.

blackzx3_13 wrote:

mndsm wrote: You might be the person I want to talk to then. What is the warranty life/what kind of cost am I looking at in getting an ESC replaced? It's an older Traxxas brushless ESC that I have in comination with a VXL motor that I got in a swapped Rustler. I FURTHER swapped the Rustler, now it's an LCG Slash (I'm rather proud of it, given as little as I have into it). I'm not 100% sure what happened, I'm told it might have overheated. No matter what I do to it though, reprogramming or otherwise- it cogs like crazy, and refuses to do reverse no matter what mode it's in. I'm told it's toast. Can you shed any light on it?

Is it the one in the project car section with the mini-van body? Cogging + no reverse is a sure sign it's been overheated. Reverse is usually the first thing to go, then the cogging starts. If it's older, the only thing we offer is a discounted replacement plan. You can send us that ESC and we'll sell you a new VXL ESC for $50 plus $5 shipping. We can replace the motor for another $35.

Yeah, that's the freakshow right there. Thanks for the heads up.

blackzx3_13 said:

Here at work (Traxxas) we tell our customers fuel has a 3-6 month shelf life depending upon how it is stored. Anything over that and it's usually bad. Also, definitely sounds like the glow plug needs to be replaced. I'd get fresh fuel and a new plug before you start addressing the other issues you described.

Traxxas customer service sucks they don't stand behind there products. Bought a tmaxx 3.3 brand new last year in spring because of my work schedules in spring summer and fall I work non stop and don't have time to use it only in winter late fall. Went to fire it up and guess what E36 M3 turned over a few times then it just locked up at top dead center freed it up tried firing wouldn't fire. Brought back to my local hobby shop where I bought it and he looked at. After Traxxas told me oh send us the motor and buy a new one. No foh I spent money for something that was broken from the start. Shop took jt opened the motor was full of some weird grease jug and piston were fine he took it mind you 15 years he's been doing this nitro. And he couldn't get it started so. Thanks buyer beware of Traxxas 

On the fuel depends on how it's stored. You can get equipment to measure the moisture but if it's just a gallon, get new. You can dispose of the old fuel by mixing about a cup full into your riding lawn mower with fresh gasoline. You're welcome.