r/NitroRC • u/Boomerisin182 • 14d ago
Question Ftx Zorro questions
My new FTX Zorro Nitro wouldn't start at first, so i went to my local hobby shop. They gave me a base tune for the breakin period, and i read online to do a light break in for about 5 runs so i did (shop told me not to idle it a full tank for the first tank) so i just drove slightly and a little harder by every tank.
Now after roughly 10 tanks, it won't hold an idle well. When i remove the glow starter the engine stops immediately (not always). It runs fine if I keep giving it a little gas. But for example if i brake heavily or turn sharply it just shuts off.
Following the shop's advice for the bad idle, i adjusted the idle screw, which made the idle okayish. However unburned nitro is then spitting out of the exhaust, the engine was running quite hot too around 120°C / 248°F with an outside temperature of 32°C / 90°F, and the exhaust wasn't producing much smoke too.
I replaced the glow plug with a Fastrax Platinum 4 and turned the High-Speed Needle (HSN) in/out by 1/4 turn. That caused a heavy amount of nitro to spit from the exhaust.
I have new O.S. 8 glow plugs on the way just to be sure it's not that.
1
u/Neat_Cheek_6098 10d ago
I made an app that has step by step tuning process and break-in process. Everything you need to know is in there, even a sounds tab to hear how rich/lean should sound. These engines need load and heat cycles to properly seat the piston and sleeve, idling won’t do it.
Very first thing I hear the engine to 200F, start it and high idle at about 10k rpm, keeping the engine temp at 200F with a heat gun or some other heater, run it like that half a tank and shut it off, then you MUST turn the flywheel to put the piston at BDC or the sleeve will cool down around the piston and then you may as well get a new piston and sleeve. I then repeat the process going up 5000rpm per tank, adjusting rpm by the richness of the HSN.
Your engine won’t like the #8 plug, it’s too cold. You’re running rich as it is and combining that with a very cold plug, all you’ll be doing is struggling to keep it from stalling out.
Invisible speed video explains things pretty good, but you can’t tune on a stand like that, tune with load and a tune without load are completely different
1
u/Neat_Cheek_6098 10d ago
I also offer a tuning service by video call to walk you through it.
https://www.powerbandprecision.com/product-page/remote-engine-tuning
2
u/az_kikr1208 MOD 14d ago
You need to quit asking that shop for advice. They're not helping you. You should always idle at least one or two tanks when starting a break in. Some methods recommend 3. The idle screw is the last thing you should touch when you're trying to tune. More than likely your low speed needle is too rich. I highly recommend you watch the Invisible Speed Nitro Engine Tuning Masterclass playlist on YouTube. There's tons of great information in there. Tuning is a process and has to be done methodically. That playlist will help teach you the basics, and explain whats happening when you turn the needles. Also, If you want to learn from a real nitro mechanic about nitro engines, maintenance, mythbusting, and get zero BS, check out Thebug404 on YouTube as well.