Stalling problem?

[Jmacca]

Hello guys.
I have a 18SS HPI engine and it starts and runs fine however sometimes while idleing after a shot of throttle the engine will die. No changes in RPM or anything like that it just cuts out, can anyone offer some advice/expertise to fix this problem?
Thanks
Jmacca

 

[alhope34]

Happens to my Tamiya 5.2 aswell. I don't think its harmfull in anyway. The idling probably lets a lot of fuel pressure build up in the fuel line from the exhaust pressurizing the fuel tank. When you go hard on the throttle, the pressure build up causes a large shot of fuel into the engine and basically floods it. At least that's my theory...

 

[ghost_racer]

hi, sounds like your low speed mixture may be a little bit lean, turn your low speed mixture needle counter clockwise an 1/8th of a turn, hopefully that should work.

 

[Scrogg]

Too rich on the LSN, they are loading up with fuel at idle. Then richen the HSN if temps start too rise.

 

[Jmacca]

LOL, That is the only problem with Nitro car advice, people give the complete opposite to other people. Anyway I think its a build of of pressure similar to what alhope34 is explaining, I have come to this conclusion because when it blows a gasket (every 2-3 tanks, SIGH), the problem stops. So I think I have to either releave the pressure or swap it out for a rear exhaust engine.

Thanks guys.

 

[Scrogg]

Years of experience and tons of research. I've shown a LOT of people who thought they knew how to tune an engine that they were wrong. My engines will have the same pinch at 4-6 gallons as they did when they had 2 gallons. I'm not the guy you see restarting his engine all the time. My engines bump over and start instantly, cold or hot. A few easy revs to clear it out and it will idle just fine. So many people make the mistake of running a rich LSN with a lean HSN setting.
Also your poorer quality RTR engines will not tune like a quality mill. I have .21 with 6 gallons of racing on it, 3rd set of bearings where just installed in it. It still runs @180-220F and screams.
If your engine cannot idle for 10 seconds without flaming out when you apply the throttle, it's too rich or you have too much oil in your fuel, wrong plug.....lots of variables.
In your case Jmacca, I know exactly what you are experiencing. It's a terrible carb on that engine. I can't even make those damn engines idle for long. I'd def. put a rear exhaust engine with a 3 needle carb on it.

 

[Jmacca]

Thanks scrogg. I don't have a problem making it idle, it normally dies after a hit of thottle. Anyway what kind of engine and size would you reccommend for my RS4?
Thanks
Jmacca

 

[Scrogg]

I'm not much on small blocks. I do know that O.S. makes some great small block engines that will make the car much faster and tune easier. I had a few Traxxas small blocks and the O.S. 21TM mid block for the Revo. Bigger displacement does not mean faster, common misconception. A race quality .12 will outrun a standard .18 and use 30%-40% less fuel doing so. The higher end engines pay for themselves in the long run. You will need the proper exhaust to match the engine you choose. O.S. has a wide variety to choose from. Just make sure whatever you pick has the same crankshaft style as your 18ss.
Anyone else who actually owns one of these cars feel free to chime in. I'm not familiar with this car. I've tried to help a friend tune his in a Firestorm. It had the same issue as yours. Idle fine for a few seconds but not much longer. Then as soon as you touched the throttle, it flamed out. We'd lean the HSN but then it would overheat and starve for fuel at high speed. It did not have a LSN.

 

[neobart]

Running a hotter plug will make it easier for the engine to overcome the sudden surge of unburnt fuel from idling.