benright

Hi, I can not get my new RC Nitro Truck to start. I am fairly new to Nitro but know the basics. With this one though, it does not try to start. Tried everything.

I noticed that the Glow Plug does not feel hot after having the glow ignitor on it for a few minutes while it is in the engine. shouldn't the glow plug be red hot if the glow ignitor is attached while on the engine? If I take the glow plug out and put it in the ignotor, then take it out of the ignitor, it is very hot to the touch. But when in the engine, it is cold after being attached for a few minutes without even trying to start. What could cause this?

samguan

remove the glow plug from the engine and the test it with a glow igniter.. if it becomes red then the glow plug is fine...(not the whole glow plug being red like you said.. the burning part which is at the bottom of the glow plug)

you won't see glow plug burning while it is in the engine.. you have to take it out.

trim the throttle up a little and then try to start... maybe it's too cold.. heat it up with a hair dryer and then try to start

benright

I have tried all of that. But you are not understanding what I am asking. I know I can't see it glow while in the engine. My question is, while it is just sitting in the engine with the ignitor attached, it should be glowing, correct? And thus, If I leave the ignitor just sitting on it for a few minutes, then take it off, then feel the tip of the glow plug, it should be pretty hot, correct? Just like when I take the glow plug out, attach to the ignitor for a few minutes, then remove from ignitor, the outer tip is very hot, in fact the entire glow plug is very hot.

So My suspicion is that the glow plug, when it is in the engine and ignitor is on it, is not getting a current for some reason. Like it is shorting out.

benright

Also, i have tried the glow plug screwed in at different amounts into the engine. When it is barely attached, it gets hot. I screw it in a bit further and test, it is hot to the touch. I screw it in half way ant test with ignitor on for a few minutes, it is not hot. So either there is no oxygen in the cylinder or somehow the ignitor is getting grounded. I am doing this with the crack shaft at 180. I also tried it at 0.

calvino

pop the glow plug out and hook it up to the glow driver, if it glows nice and bright its good, if its a "weak" orange glow charge the battery (or replace), if its emitting tons of smoke... then its time for a new one

benright

Yes, I know how to check the glow plug to see if it is good. The title of this has probably thrown people off.

Here is the question I am trying to get answered. With the glow plug in your engine. Stick the glow ignitor onto the glow plug and let it sit for a few minutes. Do not try to start. Take the ignitor off. Now put your finger down and touch the tip of of the glow plug. Is it hot?

Mine is not. It is as though the glow plug is not glowing when in the engine. If I take the glow plug out and do the same, the tip (and all of the glow plug) is very hot.

HJJFFFAA

In the engine it is not going to get as hot in the same amount of time because it can equalize temperature with the engine and the engine can more efficiently equalize with the surrounding air, simple thermodynamics. For your problem I think maybe it's not starting because your needle settings are too rich, reset them to factory, and try either leaning or richening from there.

benright

Thanks. I got it to start! I adjusted the high speed screw a bit and also set the throttle trim to be a little open at the start. It will start up but the idle is too high so I try to adjust the throttle trim down and it dies. It won't start unless I have the trim set high from the remote.

Also, fuel is being thrown out of the exhaust and the fuel in the tank is going down pretty fast for the short time it is running at high idle. I think this means the mixture is too rich. What needles need to be adjusted to avoid this? It seems if I turn in the high speed needle, it won't start. So, looking on ideas on what needles to adjust. I don't want to get them too out of wack from the factory settings so a bit hesitant on which to adjust.

thanks in advance.

HJJFFFAA

Lean out the low speed. Also make sure that your idle screw is set properly.

calvino

if the engine is broken in its safe to tweak things. T1he LSN (low speed needle)is the needle that needs to be tweaked for idle and about 1-50% throttle, the HSN is the "main" mixture needle, get the car on the street and do a few high speed runs to warm the engine up, NEVER tune on a "cold" engine, once you think the motor's at a good temp then begin by leaning the HSN 1/8 of a turn, nothing more than that, you may notice a slight performance increase, just keep on tweaking the engine untill its provided all the power it can then turn back 1/4 of a turn (you can go larger here), then do the same for the low end of the engine. I have to say from personal exprence if the motor's rich it needs a higher idle or it will "load up" with fuel very fast and then it is almost impossible to drive off. Hope that gets you up and running[8D]

DaveG55

To answer the specific question, No, if the plug is screwed into the head it will not usually feel hot to the touch after the ignitor is removed. The haed acts as a heat sink and the ignitor is not powerful enough to heat everything up.

Glad you got it started.

Maybe a little insight into why it would not start. From the factory the carb is tuned very rich. This is to protect the engine during break-in. However, since each engine is different, each needs a different amount of fuel. If your engine needs a bit less fuel then the factory settings will be providing too much fuel. That will do several things but the most important one to you is that the relitively cold fuel will overwhel the glow plug and keep the engine from starting. You can usually lean either the LSN or HSN 1/4 turn or so to help with this. I have had engines that needed to be leaned out almost 1/2 turn before they would fire up the first time. You just need to be very careful not to over lean and, once started, you may want to rerichen a bit to get the break-in done right.

And finally, unburnt fuel comming from the exhaust at this point is perfectly normal especialy if it was so rich that it would not start.

benright

Thanks everyone. I am able get it started regularly ONLY if I have the throttle trim set high on the remote. I lower it once it gets started but can not get it down to a true idle where the wheels do not spin. The engine is running a bit high and the wheels have some spin. If I lower the throttle a bit more, it will die after a couple of seconds.

I have played with the LSN and the idle. But I am not sure which direction is lean and which is rich. Also, after it dies, I have to let it sit for a few minutes before starting again. So I am not sure if I am too rich or too lean right now and which direction to go from here.

HJJFFFAA

Lean is clockwise. Richen is counterclockwise.

samguan

adjust the idle screw and see

benright

been playing with it for an hour and a half and no matter what I do, the idle screw setting doesn't seem to make a bit of difference. I got to the point where I just screwed it all the way in. Same thing. It will start, run a bit high but then die after about 30 seconds. Then I have to let it sit before starting again.

Then, I screw it way out. No difference. Very strange.

The only thing I have found is that the HSN has to be set to be rich for it to start and the throttle trim has to be opened a bit. The throttle trim is the only thing that seems to adjust the idle setting if I take off the air filter to look into the carb. The idle speed screw doesn't do anything as far as I can tell. I assume I am adjusting the idle speed screw which is the screw just below the carb air intake.

I did notice that my instruction booklet does not match what I am finding online about these engines as far as which needle is which. According to my booklet, the large needle which is where the gas line comes into is the LSN, but on web sites ,it says that is the HSN. So, this is adding to the confusion.

DaveG55

HSN = big screw by where the fuel line enters
LSN = small screw in the end of the carb slide (obviously for a slide carb)
Idle screw = small screw, usually on an angle and on the upper/back side of the carb - it varies some for different engines.

I know you probably don't have a Traxas truck but this link gves a really god tutorial on break-in and tuning a nitro rc engine and since most nitro engines are very, very similar it should help you out.

http://www.traxxas.com/support/kb_se...l&cat=0&id=276

benright

Thanks all. Getting closer. It still stahls after 30 seconds if I don't give it some gas. I have to open the throttle a bit still with the throttle trim in order for it to start and if I dial it down after starting, it will die pretty quick. Looking into the carb, it appears the air intake is much farther open than should be in order to run. I think that tells me i am running too lean and not enough air is getting mixed with fuel. Just my guess. Been working with the LSN but it doesn't seem like it matters whether it is set to be lean or rich. Same results either way. Seems something is out of wack with this engine since the idle speed screw and the LSN do not seem to have any effect whatsoever. Only the HSN and the throttle trim have any kind of impact.

Thoughts on that?

SAVAGEJIM

Everyone here is giving you great advice. So, keep on keepin' on.

Are you still in teh process of doing the initial break-in? If so, I strongly suggest you do not start your engine cold turkey like you have. I highly suggest you preheat teh engine with a hair dryer, or if you have a hobby grade heat gun, use that to preheat teh engine.

The reason why you want to do this is to help loosen up the engine some ane make it a little easier to start, and most of all, to not wear the parts in at teh wrong diameters especially when your engine is cold.

I suggest you continue to preheat teh engine even after you do teh initial break-in (the break-in as you did as per teh instructions). Your engine is not fully broken in until it probably has reached liek 7 or 8 tanks (maybe more, especially if it is a race-grade engine. I have heard of Race grade Rossi engines needing a full gallon of fuel before they are fully broken in).

Just out of curiosity, what RC is your RC? Someone mentioned Traxas and linked that tuning guide, ant taht vid is great for learning to tune nitro engines, whether it is a Traxxas or HPI of Losi, etc.

benright

This is a Redcat with a Vertix VX-10 engine. I have been letting it sit inside before any of my starting sessions to keep it somewhat warm. I will use my heat gun for the future. I am still breaking it in. I have not run it yet other than having it sit on top of a bucket. Haven't opened up the throttle yet. Ran through 3 tanks of fuel so far. I don't want to run it on high throttle until I get the idle problem figured out.