Frustrated with the Losi 8IGHT RTR first run

[ptrthgr8]

Nitro newbie here.. Spent a few weekends breaking in the .21 Dynamite engine, got it running really smoothly using 30/9 fuel, and this weekend was its first test run. Overall, it was a pretty disappointing day. This ~30 second run was pretty much the first run, and certainly the longest run. Using the same 30/9 fuel, I just couldn't get the motor tuned properly so it would keep running. I could get it to idle reliably, and starting was never an issue (started consistently on the first or second pull each time), but any time I went anywhere near full throttle, the engine would die - exactly what happened in this clip: probably hit 75% throttle for most of the run, then came around and went to 100% throttle and the engine died. I'm sure the high point setting is all screwed up now, so I'll have to go back to the drawing board on this one.

I knew nitro was more finicky than electric, but I really had hoped the first time out would be better. Oh well... still sounds better than electrics.

 

[Greywolf74]

Check out THIS thread if you havent already. Particularly the Nitro Tuning Flow Chart. I printed out a copy of this and I keep it in my backpack in case I ever have an issue with tuning I fall back on that flow chart. Usually helps me get it sorted out. Tuning nitro when you're first starting out isnt the easiest thing to learn so dont get discouraged. Youll get there!

 

[WVNed]

Are you checking your engine temps? I dont see a smoke trail in your video. An engine dying at WOT is possibly going lean and overheating which is very bad.
Do you have a temp gun? They are cheap insurance.

 

[ptrthgr8]

Check out THIS thread if you havent already. Particularly the Nitro Tuning Flow Chart. I printed out a copy of this and I keep it in my backpack in case I ever have an issue with tuning I fall back on that flow chart. Usually helps me get it sorted out. Tuning nitro when you're first starting out isnt the easiest thing to learn so dont get discouraged. Youll get there!

I will absolutely check out that thread. Thanks!

Are you checking your engine temps? I dont see a smoke trail in your video. An engine dying at WOT is possibly going lean and overheating which is very bad.
Do you have a temp gun? They are cheap insurance.

Yep, I do have a temp gun and was checking it frequently. Most of the time running between 160-170F. The hottest I saw was 203F, but that was after I left it running on the box for a few minutes at 75% or so throttle.

As I was fiddling with the high speed needle I would run rich and lean just to see what difference it would make. And, yeah, had some rich runs where the exhaust was clearly smoking pretty good. Just couldn't get the thing dialed in to where it would run for more than a few seconds under any big throttle.

Outside temp was right around 80F. Pretty windy, too. But conditions really weren't much different from when I was breaking in the engine, and it gave me no problems then.

So, yeah, I have more knowledge to acquire. Seems the nitro learning curve is a tad steeper than the one for electrics.

But I'll get there.

 

[WVNed]

The high speed needle controls the fuel air mixture a little above idle. As more air is drawn into the engine more fuel gets mixed into it.
It is supposed to be somewhat linear which is why on most engines one high speed needle works across all RPMs about 20% above idle.
So changing it doesn't just affect WOT
#1
You are running your engine too cold.
You want to adjust the air/fuel mixture so that your engine runs at an optimal temperature which is generally somewhere between 225-250 degrees Fahrenheit for most nitro engines.
It could be flaming out
#2
I would put a new glow plug in it.
#3
Are you using a fuel filter on the car? It could be limiting flow. Is your air filter overoiled? It could be limiting how much air your engine can get.
It will become rich at WOT and die
#4 Remember to make very small changes to the HSN. 1/8 of a turn is a huge difference on some carbs. When it is close adjusting the needle will mean moving the needle about the width of the slot in it for the screwdriver.

 

[Greywolf74]

160-170F is too cool. I wanna say that even for break in you want the engine up to around 200F. Normal operating temps should be somewhere in the 220-260F range. You need to lean it out sounds like to me.

You beat me to the punch WVNed.

 

[Tunedfrog]

Keeping a nitro running good and tuned is a never ending process. Don't get frustrated because it will come natural sooner than you think. Follow the advice other guys have posted and stick with it.

 

[WVNed]

Quite honestly I dont mess with the tune on my cars. About the only time I tweak them is if the temp changes by more than 20 degrees between when I run them. Cold make it richer, hot leaner. Just a little bit
If they go goofy I clean the carb. I count the turns on the needles and put them back the same way when I assemble it.
I am just bashing so I tune them to about 95% of there and leave it always on the rich side.
My cars had not been run for 2 years but new batteries or charges and they started right up with 2 year old unopened fuel. Bones Brew kept in the dark.
I never buy gallons bottles of fuel. Once opened it doesn't keep as well.

 

[cbaker65]

There was absolutely NO smoke!..

 

[alfredwong2003]

Too lean, plus, it also sounded like a bit of drag on the engine, maybe it is not fully broken in yet.

 

[Arrmajunk]

Nitro newbie here.. Spent a few weekends breaking in the .21 Dynamite engine, got it running really smoothly using 30/9 fuel, and this weekend was its first test run. Overall, it was a pretty disappointing day. This ~30 second run was pretty much the first run, and certainly the longest run. Using the same 30/9 fuel, I just couldn't get the motor tuned properly so it would keep running. I could get it to idle reliably, and starting was never an issue (started consistently on the first or second pull each time), but any time I went anywhere near full throttle, the engine would die - exactly what happened in this clip: probably hit 75% throttle for most of the run, then came around and went to 100% throttle and the engine died. I'm sure the high point setting is all screwed up now, so I'll have to go back to the drawing board on this one.

I knew nitro was more finicky than electric, but I really had hoped the first time out would be better. Oh well... still sounds better than electrics.

Its way too lean . You gotta richen that up .both low end and too end the idles jumping because it’s either got hot or too lean , then driving it it cuts out because you starved it of fuel

 

[newnitro2020]

Nitro newbie here.. Spent a few weekends breaking in the .21 Dynamite engine, got it running really smoothly using 30/9 fuel, and this weekend was its first test run. Overall, it was a pretty disappointing day. This ~30 second run was pretty much the first run, and certainly the longest run. Using the same 30/9 fuel, I just couldn't get the motor tuned properly so it would keep running. I could get it to idle reliably, and starting was never an issue (started consistently on the first or second pull each time), but any time I went anywhere near full throttle, the engine would die - exactly what happened in this clip: probably hit 75% throttle for most of the run, then came around and went to 100% throttle and the engine died. I'm sure the high point setting is all screwed up now, so I'll have to go back to the drawing board on this one.

I knew nitro was more finicky than electric, but I really had hoped the first time out would be better. Oh well... still sounds better than electrics.

How open do you have the idle Gap I'm just curious?


Number to the low speed needle is lean because as you let go of the throttle and as it idles it has that blurt blurt sound.

 

[ptrthgr8]

How open do you have the idle Gap I'm just curious?


Number to the low speed needle is lean because as you let go of the throttle and as it idles it has that blurt blurt sound.

I left the low speed needle set at the factory setting. I had seen a few videos where folks stated the 8IGHT RTR came with a properly set low speed needle. But I did remove the air cleaner and looked into the carb to see how much of a gap was present and it looked okay to my newbie eyes - not closed, maybe a millimeter or 2 of a gap? Haven't had any issues yet with it idling, so didn't pay much attention to that possibility.

 

[Greywolf74]

I left the low speed needle set at the factory setting. I had seen a few videos where folks stated the 8IGHT RTR came with a properly set low speed needle. But I did remove the air cleaner and looked into the carb to see how much of a gap was present and it looked okay to my newbie eyes - not closed, maybe a millimeter or 2 of a gap? Haven't had any issues yet with it idling, so didn't pay much attention to that possibility.

1-2mm is typically were it should be

 

[ptrthgr8]

Today was my first chance to fiddle with the tuning since the last time out. I did adjust the high speed needle so it's running richer now. Video below shows a quick clip I took - wasn't able to open it up to full throttle (only have two hands and didn't want to risk it launching of the table), but off camera I did get it max a full throttle quite a few times without it dying. So, it now idles well (doesn't die anyhow), I can give it varying levels of throttle and it keeps running, there's a lot of smoke now, and it sounds epic at full throttle. Not sure the neighbors love the sound... but that's okay.

It was 72°F when I was outside, with barely a breeze. I used my heat gun to get the engine warmed up to 210°F before starting. At idle, the temps were between 170-180°F. After running with half or so throttle for a while, temps were in the 200-220°F. And after running at full throttle for 3-5 seconds, the temps were between 240-260°F. I didn't want to run it too long at full throttle since there wasn't any air moving through the heatsink.

Will see if I can get it out for another run to see how it does with this tuning. I assume I'll need to tweak it a bit to be optimal, but I'll be happy if I can simply get it to run reliably.

Cheers!

 

[newnitro2020]

I left the low speed needle set at the factory setting. I had seen a few videos where folks stated the 8IGHT RTR came with a properly set low speed needle. But I did remove the air cleaner and looked into the carb to see how much of a gap was present and it looked okay to my newbie eyes - not closed, maybe a millimeter or 2 of a gap? Haven't had any issues yet with it idling, so didn't pay much attention to that possibility.

As a beginner to now a proud intermediate individual.


That low speed needle in his way lean. You hear that stutters sound on idle.



And when you drove the car the car suddenly stop inflamed out.

That's a sign of two things 1 your idle is Way open or you're low in is way too lean.


Allow me some time to respond and read your full message but I just saw your video I just saw you for the first time today.




I'm reading that you left your low-speed mixture at the factory setting which is good. So the next scenario would be that your idling Gap is too wide. All right so it looks like it's one of those ready to runs where the factory people set the idle where and I've had this problem before.


A scenario where the idle is set either too wide and then the engine doesn't run right when you either breaking in or when you try to run it like a normal person this is something I can't discuss over text I'm going to have to send a video response to you.


But all I can tell you is this that you have to have at least on one millimeter Gap and that's a good setup. 2 mm is overkill.


Sometimes even if you have the proper factory settings you're injured may not run right because of the kind of fuel or environment as far as atmosphere that you you living at.


Allow me to help you. I'm going to do a video in a little bit.

 

[Tunedfrog]

 

[Greywolf74]

Today was my first chance to fiddle with the tuning since the last time out. I did adjust the high speed needle so it's running richer now. Video below shows a quick clip I took - wasn't able to open it up to full throttle (only have two hands and didn't want to risk it launching of the table), but off camera I did get it max a full throttle quite a few times without it dying. So, it now idles well (doesn't die anyhow), I can give it varying levels of throttle and it keeps running, there's a lot of smoke now, and it sounds epic at full throttle. Not sure the neighbors love the sound... but that's okay.

It was 72°F when I was outside, with barely a breeze. I used my heat gun to get the engine warmed up to 210°F before starting. At idle, the temps were between 170-180°F. After running with half or so throttle for a while, temps were in the 200-220°F. And after running at full throttle for 3-5 seconds, the temps were between 240-260°F. I didn't want to run it too long at full throttle since there wasn't any air moving through the heatsink.

Will see if I can get it out for another run to see how it does with this tuning. I assume I'll need to tweak it a bit to be optimal, but I'll be happy if I can simply get it to run reliably.

Cheers!

Sounds a lot better. As long as it doesn't go much over 260ish when its moving you should be good.

 

[Tunedfrog]

That actually sounds pretty good.

 

[cbaker65]

That engine is loading up on idle ,that is why there is way too much smoke ,if it sits there too
long on idle ,it will flame out do to the rich Lsn. ,but also ,it is good to get your high needle
tuned first to where you want it ,then lean the Lsn. a little off of factory ,about a width of a
screw drive blade at a time ,until the throttle response becomes snappier an some of that
smoke goes away ,you will may need to alter the idle gap as you go to lower the idle!..