You may have the best failsafe unit installed; this will not prevent your vehicle for a runaway. Failsafe units are good for radio interferences or when the receiver pack is low but what will happen if your throttle linkage falls or breaks? What will happen if your receiver pack or your throttle servo disconnect? In all those cases, your slide carb will remain fully or partially opened and nothing will force it to close. This may result in a spectacular runaway or in a “tire ballooning contest” if your vehicle is upside down. Everybody will be looking at your vehicle without knowing exactly what to do to stop your engine. Meanwhile, your engine will be full wide opened during precious seconds. Not exactly what we want for our engines, no matter what are the price, age or quality of the engine. Not mentioning this situation can be dangerous for anyone near your vehicle. Imagine what can happen when someone gets hit by a 10 pounds vehicle running at 40MPH!
This is where the throttle return spring is a must. Not just a must for die hard racers, but for everyone who runs a nitro vehicle. Some vehicles have a throttle return spring (TRS) installed at the factory but most of the vehicles don’t have a TRS installed. The same is true when you purchase a new engine. Rare are the engines that come with a TRS. The solution is quiet simple and costs less than 4$us. It is a really low investment to save an engine! And someone’s ankle! All you need is a zip tie (we all have ones in our tools box) and a throttle return spring designed for the Team Associated RC10GT/GT2 (PN: ASC7562).
- Remove the air filter.
- Disconnect the throttle linkage from the carburetor.
- Insert the carb’s ball stud (where the linkage connects) into the loop at one end of the spring.
- Insert a zip tie into the second loop and tight the zip tie around the carburetor, near the fuel inlet.
- Make sure the spring is loaded enough to fully close the slide carb.
- Reinstall the throttle linkage.
- Reinstall the air filter.
- Turn on the transmitter and receiver and verify the carburetor operates freely when you apply throttle. Don’t start the engine. To test, while applying full throttle, turn off the receiver switch. The throttle servo should go back fully closed. If not, the throttle return spring is not extended enough. Reinstall it farther over the fuel inlet.
Yes that’s all. This mod will not make you faster or make your vehicle handles better but this is the cheapest and the most “responsible” mod you can make to your vehicle. And in case you ignore it, TRS are mandatory on my race tracks for safety.