farknben

Hello, I got my first nitro vehicle last night, a MGT. I never broke in an engine before and was having a little trouble getting it going. If I gave it about 1/4 thorrtle it would keep running but would stop once I let off. So I tried to adjust everything(Idle needle, hsn, lsn) several times with no luck. Finally I thought I would increase the throttle trim on the radio until it would idle(maybe a bad idea?).

So it runs fine except when I brake then it stahls out. Ive searched everywhere for help with no real luck.

Any ideas? Maybe it will stop once brakin is complete? Ive done 3, 3min cycles like this.

If you can, please help

Thanks in advance,

Ben

aer-wubby

Air could develop in the gas line when you release throttle I think. You should check the line to see if there are any air bubbles.

duckedup

Are you using the heat cycle method? or the manual instructions?

... the truck comes from the factory set for their break-in method and is very rich, which is probably why it's stalling (could be the idle also). Start from factory settings and 1st try leaning the the high speed needle by 1/8 increments just 'till it stays running, you shouldn't have to mess with the low speed mixture yet. And yes, new motors are temperamental during break-in...

Turning up the throttle trim is a good way to get it started at 1st but when it's warm it should stay running with that set normal. If it's still stalling out, then turn your idle up slightly but not too much - to set your idle properly, the motor needs to be warm (close to normal operating temp).

farknben

Thanks guys.

There are a few bubbles in the line.

Im using(trying) the heat cycle. Ive already tried to rest the factory settings.

Im such a nOOb to this.

It seems to really be blowing out ALOT of oil! The rear right tire is pretty covered in it. I assume that means its running way too rich? And Im only getting like 5-6 mins a tank.

I just ran it for a few minutes then it till it ran dry. Now its dark so Im done till tomorrow.

Any follow up help would be great.

Im NOT going to give-up. I will win. Even if it means I screw something(engine up) up.

Wow that last line dont sound like me???(kinda stubborn)

Thanks you 2

duckedup

When you're breaking it in using the heat cycle you want the LSN and HSN settings to be close to what they would be after normal break-in, not too rich but not too lean.... factory sttings are way too rich for heat cycle

farknben

OK Thanks Ill give her a try. What about a 1/2 turn lean of factory?

When it was going, MAN was it sweet. Ive never driven a nitro before. I think Im gonna love it.

farknben

Oh! one more question, for the idle- how and the hell are you suppose to measure .5mm? Thats crazy, as long as Im close(say within another .5mm) should I be OK?

duckedup

yeah, just get it as close as you can to what it looks like in the manual, doesn't have to be perfect - just close. When it's warm, adjust the idle while it's running so that it's just low enough so that it doesn't go anywhere while the throttle is in neutral, you'll probably have to re-adjust it when it's broken in.

for the carb settings - I run 6 1/4 out on the LSN and 2 1/4 out on the HSN - temps are between 240-250 range.... Settings are going to vary depending on your climate and outside temps. You should go over to the Dirt Burners thread and ask Bria1, he races a MGT (I think) and would probably be more help since he's in your area (well, MI at least)

farknben

Thanks for all your help DuckedUp. Ill let you know how it goes tomorrow.

Bria1

Looks like duckedup has you going the right direction. The important thing for heat cycling is that it actually gets up to around 200 degrees. With nitro, don't make huge 1/2 turn adjustments. Think of the needles like the hours on a clock and make 1 hour adjustments at a time, 2 hour adjustments at the most. Break in takes patience, don't rush it. Take your time and you'll get more life out of the engine. And always use after-run oil. It keeps the inside of the engine from rusting and make sure you run it out of fuel before putting it away.

farknben

Im starting to get a little frustrated. Today I cant seem to get it to started unless the throttle trim(on the radio) is at full cw. When I do get it going, I cant turn the trim back down or it dies. ???

duckedup

turn the idle screw out a little.... when you're throttle is in neutral, check your linkage and make sure your brakes aren't engaging - I didn't check that at 1st and my brakes were dragging because the out-of-box settings were off .... Don't get discouraged, break-in was a pain for me also and that was before I knew I could find help online - talk about frustrating lol

duckedup

Do you have a temp gun? if you can't tune by the sound of the motor yet (sound or amount of smoke), having one makes heat cycling much easier

Bria1

Change your glow plug. These can go through glow plugs pretty quick from running so rich during break in. How is your idle setting. You may have to lean it out some. I know it can be frustrating when you're just starting out. How many tanks have you got through it now?

farknben

Just got done trying to run another tank. Ive ran 4.5 thru it. And 3 glow plugs.

I did some more searching on the net. And found an article about air leaks making it very hard to tune a new engine. So I took of the engine and did the test they recommended(blow thru a fuel line on the carb, cover the airfilter hole, use soap to find bubbles). Well its leaking around the carb and the front bearing. Im kinda pissed, since I never took the engine apart.

So Im going to call AE tomorrow and see what they say. Maybe I can send it back for another. I usually wouldnt ask for such treatment but I think thats why its running so eradict. I hope there cool(Ive never had any problems or had to call them before and this is my 7th car from them, thats the main reason I went with the mgt).

Well wish me luck or tell me Im a dumbass for thinking this is the problem.

Thanks for help again you 2

duckedup

leaking around the main bearing?? usually when motors leak, it's from around the carb or the backplate... sounds like a warranty issue, that sucks... there aren't usually too many complaints about these motors but it happens

duckedup

You know, if it was just the carb or backplate leaking, you could seal it up with a little RTV like copper seal or something (as long as the gaskets are still are ok). But if it's the main bearing then I'm pretty sure you need it replaced... just a thought

farknben

Yeah...the bearing behind the flywheel(The web article I read said it was the "front bearing" ) I figured I could do the carb or backplate aslo.

Is there suppose to be a gasket between the block and backplate? Because thats the only thing I took off. The owner of the LHS said to take it off and the glow plug, and put a little glow fluid in it and turn the flywheel over a few times. Then drain and rinse again. Then put back togahter. He said it would get out most of dust(as opposed to trearing the engine totally down). Any ways there was no gasket in there. I dont think the manual shows one either.

I sure wish that I still lived a few miles from Costa Mesa(they're HQ). Ill call them up tomorrow well Im at work and see what they say. I hope their as cool as the guys at Losi.

ThermalRD

Some motors have a gasket at the backplate, and some have an O-ring. I think its more common to see an O-ring there. If you dont see either, take a closer look. I remember one of my motors, not sure which one, had a gasket that was some kind of transparent color. Like a thin plastic gasket. Was hard to see on there. So take a close look. How bad is that front bearing leaking? Its very common for these motors to have leaks there. The situation can also be over exxagerated during break-in as well. I'd finish break-in, and tune it up. If its got an excessive front bearing leak, then warranty that motor. It also sounds like you are extremely rich during this break-in. If thats the case, you can throw that heat cycle right out the door. You have to get those temps up for an actual heat cycle. In fact, i reading up there you have 4.5 tanks thru this truck? Its broken in. Doesnt matter how good at this point, its broken in. Once you get that idle straightened away, do a pinch test on that motor. Get it running, and up to temp. Pinch the fuel line about 1.5-2 inches behind the inlet on the HSN. If it shuts off right away, yer lean. Which i dont think is the case here. If it takes 5 or more seconds to shut off, yer way rich. Lean it out an hr at a time, til it shuts off at about 3-3.5 seconds. Once its tuned up, see how bad that front bearing is really leaking. You also mentioned going thru plugs. Are the plugs in one piece when you remove them? As in, the coil still inside the plug? If its not, then you likely have that coil, from the original plug that blew up, somewhere in your motor. Which will cause the other plugs to blow up.

duckedup

these motors have the O-ring, that's what I was talking about when I said gasket

farknben

Oh yeah I forgot I did see the o-ring.

I did the pinch test and it would run for about 6 secs and the rpms would sky rocket. So I tried to lean out the HSN but it didnt do much, I went as much as 2 turns(only 1/8th at once) it was also still running cool, comfortable to touch, after about 2 min turned that much. Some times it would start back up after stahling sometimes not. This is why I think it maybe the air leaks. Like some times it would start up and sound great, Id get a big smile and in a few secs it would start burbling or rev high or stahl. Then some times it would do the opposite. oh and yeah it was would do this when it was worm. Up, down, left, right; I was never sure what it would do(I dont think it did either)

The plugs are intact. I just think 2 of them are bad because they dont glow nearly as bright as the other one. There all the same plug(stock ones).

I did put the engine back in and try to tune it again but no luckIt will still only start at throttle trim full clockwise. i took of the air filter and its open about 3/16". Which makes me think even more its an air leak, so it needs more fuel. You think?

The good thing I guess is it still has alot of compression.

Bria1

Some times it is best to stop, reset the needles and idle and recheck it. Set the idle to be .5mm to 1mm, set the low speed to 6 1/2 turns out, and set the high speed to 2 1/2 turns out. Put it on something so the wheels are off the ground and can freely spin. Start it up and rev it a few times to clear it out and try to warm it up. Don't go wide open, just short bursts. Run it on the ground now. If it still acts rich, turn the high need 1/8th turn and recheck. Do you see a lot of fuel on the chassis by the flywheel? If there isn't much, I doubt you have a bad enough leak at the front bearing to cause a problem. If it is leaking around the carb, use some O2 sensor safe RTV sealer to seal it up. I just put a dab on a small flat screwdriver and spread it around the portion of the carb that goes into the engine case. Don't use too much or it will get inside the engine. Too me it just sounds like it is too rich. Usually if you have an air leak it runs hot because it is too lean.

ThermalRD

Fark, for starters, you mentioned leaning the HSN after the pinch test. The pinch test would show you where your LSN is set at. Which is also known as your idle mixture. Lean the LSN and test that pinch test.

MBX5T Maniac

My Feedback: (-1)

Well since the front bearing is leaking, I would just have the engine replaced.

badboy2

My Feedback: (13)

did u even try to open the carb a bit ?instead of turning the th trim all the way just set it thru the idle needle..