GXR28 Constantly stalling, need advice

[kusok]

Hi Everyone, I am new here and new to this hobby, however I am quickly getting dissapointed by my experienced.

I got a Kyosho Inferno ST US Sports with a GXR28 engine and have been having trouble with it all the time.

First off: it's really difficult to start. In about 20 hours I have been trying to break it in I had to discard 3 sets of duracell D batteries for the heater. When I get it started it cannot idle for more, than 30 seconds - stalls.
If I give it more RPM (gently adjust throttle trim), it starts to run, but stalls in a few minutes. It doesn't seem to be overheating, because if I drop water on the engine it vaporates normally, without crazy clicking (as when it's too hot). It also doesn't seem to be too rich, as the engine doesn't sound like it's choacking on fuel.

Basically I couldn't even break in it propery. Overall 2 tanks went through it and the stalling issue doesn't seem to be improving. I have tried both leading / richning the HSN, LSN and also tweaked the carb opening (the carb I tweaked so that it wouldn't stall when breaks are applied with maximum force).

Any ideas what am I doing wrong? I have heard, that the GXR28 is tricky, but I couldn't have imagined this. I am willing to provide any additional info if you need it, just please help.

Dennis

 

[olds97_lss]

Engines are really flaky when they are new. I'd suggest getting a sub-c rechargeable heater. The sub-c allows the glow plug to draw more current than alkalines which gets the glow plug nice and hot. Alikalines loose their punch pretty quickly as a heater battery.

Sometimes you have to leave the heater on the GP for 20-30 seconds after it starts so you can throttle up and get the engine to warm up a bit. Especially during break-in.

What fuel are you running?

 

[kusok]

hmm, but it's interesting to see, how all those manuals show, that break in should be easy. So you would suggest, that I try to keep it starting all the time, until the break in is complete? I am worried, if it is stalling its not reaching the right temperature and it will never break in. So far, these attemps were like workouts for me (pulling the recould all the time) ... damn recoil starters.

But throttling isn't helping in the long rung. I agree, that it does help initially, but like I previously described, it still stalls after around 5 minutes, without reaching the correct temperature. It really troubles me, as I can be breaking it in indefinately like this.

I am using kyosho 16% nitro fuel.

 

[olds97_lss]

Even if you apply throttle lightly/slowly with the heater still on the engine? For the first few tanks, you typically don't get past 1/2 throttle anyway. The engines just don't run well until about 500cc's of fuel are through them. The pinch is too tight. Some take 1000cc's before they run stable.

My LRP28 was picky for about 8-9 125cc tanks. Around tank 10, I started leaning a bit. Around 2000cc's (1/2 gallon) the power started to come on. By 3/4-1 full gallon it was starting easy, idled well and after a full gallon, the engine came to life and power was great. I now have about 4 gallons through it and the power on tap is the same as it was around a gallon.

Just give it time. I'd suggest tuning back to stock and lean it about 1/4-1/2 turn on the HSN. Get it running with the wheels off the ground and slowly run up through the RPM's. Don't go past 1/2 throttle though with the wheels off the ground, the engine is too new. If you can get it running, drive in a big lot (pavement) and drive from idle to 1/2 throttle slowly and let off. Keep doing that. When the engine seems to get to peak temps (normally around 160-170F until tanks 3-5), shut it down, put the piston at bottom dead center and let it cool back to ambient. Typically by tank 5, your able to lean it enough to get the temps up to 200F. I typically don't lean for performance until 1200-1400cc's of fuel have been through it. I lean to get temps up and thats it.

After each tank, let it cool down with the piston at BDC.

Your aware of priming the carb, correct?

 

[kusok]

ok, so it finally stopped raining and I found some time to take the car for a drive. It seems, that the solution is coming to me now. The reason why it is stalling is clearly the LSN. I can now say, that with confidence, as when the engine warmed up today the acceleration was terrible: I give it half throttle...it thinks for 2-3 seconds and only then starts to accelerate. As far as my knowledge goes, the engine gets way too much fuel.

The starting issue also seems to be resolved. Does the glow plug have to glow, when you put it into the heater? In my case it doesn't glow. So I am guessing I should get some rechargeable heater, because alkalines do indeed suck. I didn't get 10 minutes out of the last pair.

Thanks for the help so far. When I get this new heater I will try once more, my guess is that starting should become a lot easier.

 

[helotaxi]

While you're at the hobby shop getting a new heater, go ahead and get a few glow plugs that are one level hotter than what you have been using. The hotter plug will help keep the engine from stalling with richer than normal carb settings that are used during break in.

 

[aussienitro]

Hi I posted this on another forum, I hope this helps you out... I feel your pain..... I had the same problem when I first got my Kyosho GX21 engined buggy a few years ago... now since the GXR28 uses the same carb I can tell you exactly what the problem is as I spent weeks pulling my hair out trying to tune it!!
Someone else hit the problem dead on... it is the inner o ring on the low speed needle leaking fuel past it into the engine!! what happens is you have 2 o rings on the low speed needle, a small one on the inside and a larger one on the outside... the small o ring stops fuel poring into the engine and forces it to go through the needle as it should, when it leaks no matter how much you adjust the settings it will just keep pouring too much fuel into the engine hence it will never tune and run way too rich all the time, I worked this out by sitting down one night after weeks of trying to tune it and figured out this must be the problem! DO NOT USE THE STANDARD KYOSHO O RINGS!! they are too small and that is why you have problems with them.. my advice is (as I did) find a good o ring shop and take the original ones down with you or the needles and carb so they can measure them and replace them with better quality o rings... since doing that I have never had anymore problems tunning the buggy