SparkedFlyer

Ok, so I've spent a few days trying to enjoy my new LST 2 but have been largely unsuccessful. I've had it running about 30 minutes total in three different outings. The truck is fine it's just I'm having a tough time starting and tuning it. The motor has already been broken in. I can get it started but then when it shuts off, it's really hard to start again. I remove the glow plug and turn the truck upside down and turn over the motor, and although no fuel comes out, when i put the plug back and try to start it starts back up just fine. Does this mean I'm running too rich and fuel is building up in the motor? My temps are in the low 200's and I don't have a lot of smoke, just a visible trail. Do I have to wait for a hot motor to cool before it will start again? I'm brand new to this and I've read countless tutorials on tuning, but I just am having a tough time. Can anyone that owns an LST2 help me out here please??? This thing is seriously about to go on Craig's List if I don't get the hang of it. The worst part is I bought a bunch of hop ups thinking it was going to be easy. I've spent like a thousand bucks on this thing! It's very frustrating.

1. Any advice on starting, tuning, and restarting?
2. How far of from the factory settings should the needles be roughly (factory is 4 turns out high speed, and 2 turns out low speed)? And the manual doesnt mention anything about where the idle screw should be.
3. In the Mach 27 manual it says the "it's crucial to have the carb slide completely closed when adjusting the low speed needle". What does this mean? I talked to Horizon support and they were no help with this.
4. In what order should i set the needles (I know high, then low, but what about idle?)when starting all over?

HELP PLEASE!

str8jailbird

About 1mm for the idle screw. By that I mean the slide should be open about 1mm with the idle screw. A little more info on your problem. Does the engine die when you hit the throttle? If so it sounds to rich on the high end. I have the LRP spec 3 and I am set at about 3 turns out on the high and 2.75 on the low. Factory settings are always extremely rich. Leave your glow starter on and rev the engine to get it up to temp. If it won't stay running like that keep leaning the high speed needle until it wilol. Do the pinch test for the low speed. When the engine is idling pinch the fuel line and iuf the engine runs for a few seconds and then starts to rev higher it's set ok. Check this out. And you came to the right place. Ton of folks here to help.
http://www.*********.org/cars_eng-tuning.htm

RenegadeRevo

My Feedback: (1)

I feel your frustration. I was feeling the same thing after putting in my 3rd Mach 427 in less than a gallon. Usually when a motor doesn't start after it gets hot, that means compression is lost. Before looking into a new engine, I would suggest trying a few things:

1. Check for air leaks... replace fuel line (pretty cheap fix)... check your tank for leaks (specifically the primer as it has been known to cause problems)
2. Replace your glowplug
3. Try new or different fuel

As for answering your questions...
1. When in doubt, take it back to factory settings... tuning a nitro engine is not a one-time process. It's part of running as the atmosphere changes (hot, cold, humid, dry...etc). Most of the time, you can get it tuned in, then make small adjustments per the conditions.
2. I believe STR8jailbird covered this one a little... how far you are from factory depends on the conditions and the engine. There is no "perfect" tune that everyone should run at. I would say, if you're 1 turn from closed... or 10 turns from closed, you are probably a little out of tune.
3. That just means to make sure you're not on the throttle when you're adjusting the needle as it goes in and out with the slide and can become damaged if you turn it in or out while it's not at the "closed" position.
4. The way I've tuned all my engines, and I was taught to tune these engines is as follows:
Take the needles back to factory specs (4/2, I believe). Start the engine and warm it up to normal operating temp, running a few WOT runs or just playing around for a minute. When you're confident it's been warmed up, bring it back to you. If you tune per temp, take a temp reading. These engines run really well between 230 and 260. I usually keep mine at 255-260 when I'm paying attention to temp, but that's just me. If you've returned your needles to factory, you probably won't even be close to this range.... turn it in 1/8 turn increments to adjust the setting. Run it WOT a few times up and down to get the tune "applied" then bring it back. Take temp... and continue. Once you feel your HSN is dialed-in, turn to your LSN. This will give you throttle response and idle time. There are a few ways to test this, one is a pinch test. Hold the fuel line and pinch the fuel off. It should idle up and die within about 3-5 seconds... if it's faster than that... you're too lean, if it's slower than that... you're too rich. Adjust the same as you do the HSN... small increments with a few WOT runs in between. Don't adjust idle unless you HAVE to as adjusting the LSN will adjust your idle a little bit. Once you feel your HSN and LSN are adjusted, make sure your truck idles. It should idle low enough to not engage the clutch, but high enough to keep the motor running.

Alternatives: Non-temp tuning is better, but it takes more 'skills'. Tune to performance and smoke. Your engine will create more power when it's leaned out, but if you go too far, it will tell you. I usually start at the baseline, lean it out slowly, and tune to performance. You should have a nice stream of smoke coming out (not billowing out like a fire.. just a very light hazy cloud) If you have a temp gauge, I would use it just to make sure you've got it in the right temp range... if not... use the spit-test... take a small amount of spit and apply it to the head (be careful as the head on the truck is HOT) it should sizzle off in about 4-5 seconds... if it doesn't... it's too rich... if it sizzles off quicker... it's too lean. LSN can be tricky with the LST2 using the pinch test. Another way I've been taught is to let it idle for about 30 seconds. If it can idle that long without dying, that's a good sign. If it can't... that means you're probably too rich on the LSN. Once 30 seconds is up, go WOT... it shouldn't bog... if it does, you need to adjust (most likely need to richen it up) if it's peppy and it takes off... it's tuned right.

Tuning takes some time to get used to. There are many different ways and skill levels out there. Don't be afraid to ask a local hobbyist for some advice. That's how many of us learned. (We all were noobs at one point)

ARDV8

Is the truck used, or new and you broke the engine in.

There are a few ways to break the engine in. I like to try and fire it up with the needles set at factory settings. I then just let it tick over for a tank. The temps don't get very hot, but I think it gives the pistons chance to bed in slightly with a very rich oily setting.

Then I crank the HSN about half a turn closed and push another two tanks through it. Then get the truck on the ground and start tuning. A lot of people won't like this method, but I have two engines with over seven gallons on them and still running fine.

Also, you might want to check the fuel filter, also if the fuel lines are running close to the engine that might be causing the fuel to evaporate.

When you have had the engine running have you checked the temperatures, if you have post them up as these can be a good indicator of if the engine is rich or lean.

Is your fuel ok, it can go bad if you had it a while. Also what glo plug are you running, and what % content fuel

SparkedFlyer

Thank you all for your responses so far. The engine does not die when i hit throttle, it did a couple of times but i leaned the HSN and that took care of it. Also, the truck is new and i broke it in using the heat cycle method. I use Byrons Gen2 20%. I'm a little scared about the no compression comment. The engine does start when the needles are set correct, it;s just restarting seems to be a pain. Should the engine fire right up when hot? I've checked for air leaks and it seems OK. The motor still makes a muffled "popping" sound when turned over so I'm pretty sure it still has compression. Could I have ruined the engine that easily and fast??? Now I'm worried.

full maxx

try to stick with it ...my first was a cen genesis (pos) almost impossible to tune or at least i thought it was but it kept breaking stuff w/o reason but then I got a lst2 and love it , mine has seen ten gallons , nine on the first mach but the trick to tuning is there is no setting carved in stone as to where to set what except the idle and everyone is agreeing about 1mm on the slide which is under the air filter so you will need to remove it to see it but like others will say when in doubt always go back to factory settings and retune ...it will take a while but you will be able to tune by ear in no time also these nitro engines take about 1/2 to 1 gallon of fuel to wake up and not be so tight but be patient and keep trying it took several quarts for me to get the hang of it also the tune you had that was good yesterday may not be right today like everybody will tell you a change in temp outside by a couple of degrees will affect your tune as will humidity and elevation ...the cooler the temp outside the more dense the air is which means that more air is getting in your engine and you will need to richen it up a bit just as hot temp outside will make the air thinner and you will need to lean it a bit but have faith with time you will get it and if you are like me once I did I was running a gallon a week in mine , nine weeks later the first mill was gone and now I'm a gallon into the second ... but you got the toughest truck there is hands down ...

SparkedFlyer

BTW...what causes compression loss (premature)? It's basically new so why would it lose compression already? I haven't run it lean at all. Temps have never exceed 265-270.

str8jailbird

If the truck is brand new and just broken in I doubt that you have a comnpression loss. Possible but unlikely. Compression loss is usually caused by a variety of problems. Bad bearings, sleeve/piston fit, head button cracked (have yet to see that occur) or even the head bolts loose. A loose glow plug will also do that. Your temps are a little high for my taste with the Mach 427. My LRP runs a little lower than that when hot. Those aren't dangerous temps but getting close. Not to sound like a broken record but like RenegadeRevo said, might be an air leak. Check fuel lines and filter. Also take off your fuel filter and check it. If there is fuzz/dirt on the screen this can explain a lot. Just had this happen to me and I check mine after every 2 tanks or so. Ran the truck after checking the filter ran 1.5 tanks and it started leaning out on WOT. Took the filter apart and voila, clogged with what appeared to be lint. Live and learn, still trying to find out how that happened. GOOD LUCK!

glk420247

I had the no starting problem, when my truck got hot also. I took the primer pump out and sealed it up with some Permatex gold. It helped a lot. I also had problems with the type of glow plug I was using. I personally don't like the OS 8 I switched to mcCoy 59 and smooth running ever since. Good luck and stick with it, because once you figure it out what is wrong you will be glad you didn't sell your truck. My 2 cents.

full maxx

not sure if you are familiar with putting the piston at bottom dead center after running or not but if not it will kill your engine a lot sooner than it should remove the glow plug and watch the piston when it is at the bottom take a sharpie marker and mark the fly wheel so every time you are finished running out that tank or when ever you stop running for even 10-15 minutes put the piston at the bottom of the stroke to cool if not the cylinder will not shrink back to the correct size and it will cause a loss of pinch which will lead to a short life engine

SparkedFlyer

I don't run at 265-270 constantly, that's just as hot as I've seen it run. I usually stay around 230. I'm using McCoy 59 plugs already. Is there a good way to test for air leaks? I made sure everything is tight but then again I could be missing something. I will check the fuel filter also. Also, when is the glow plug finished? Is it when just the very tip of the plug is burned out or when the first or so coil is burned? Every time I get it running for one or two tanks, I get happy. Then, I'll run out of gas and it shuts off. Thats when it's back to the frustration. It's a real pain to start back up.

Redharris

I may be wrong, but isn't the MC59 a HOT plug.
I THINK my buddy uses those plugs in his Small Block .18 engines.....

I believe you should be using a Medium Plug for a Bigblock, (I know I do).
Something like an O.S. A8 plug, which is what I use in my sh .28 engines.....

RenegadeRevo

My Feedback: (1)

I didn't mean to worry you... but it is a possibility. That's why I took a step back and mentioned other things to check before worrying about compression. The advice you've been given in this thread is pretty solid. You should be able to troubleshoot most of it. If all else fails, put in a trouble ticket with Losi and have them give some more suggestions. They're pretty good, once they actually respond. They've been pretty slow to respond to my requests, but they've always helped me out... they may even have you send in your engine to look at it. That's what happened with mine... they replaced the piston and sleeve... and sent it back.

2DMaxLST!!

I would suggest seeking out someone with more experience in your local area to give you a hand. If there is a local track I would go there with it, most racers would be glad to help you in person. I went through a few engines before I got the hang of it.

SparkedFlyer

I appreciate your advice - it's sounds good and I'm not to worried as I can always send to Losi like you said. Another thing I noticed is that my fuel tank smokes. When I refuel, I open the tank and I see what looks like smoke in the tank. Is this normal? Also, I seem to get fuel dripping from the pipe, is that normal too? It's several drops - not a ton of fuel, but there is some.

SparkedFlyer

I thought that too, but the Mach 27 manual states specifically that the "MC-59 is the absolute best plug for this engine", so I'm using that one. Do you think a medium-hot plug would help my situation?

full maxx

the smoke in the tank is normal as the exhaust pressurizes the fuel tank to push it to the carb and oil dripping from the exhaust is normal to a point as this is a result of combustion of nitro fuel as it is mixed with oil to lube the engine but all the oil does not burn and it has nowhere else to go,but like 2D said if you have a track near by people there will be glad to help or your local hobby shop but make sure the guy at the hobby shop knows what he is doing as I have heard horror stories about taking it back to the hobby store...you might want to do [link=http://www.savage-central.com/modules.php?name=Forums&file=viewtopic&t=54465]this [/link] I sealed both my mills like this and I never had a tuning prob until I found mud in my tank and my fuel filter was clogged with it causing a really lean condition but it runs like a champ now, look up lst videos and watch some and see what your truck is capable of oh yeah I use mccoy 59 as I have found they last the longest and as far as the plug goes if you are useing the same one used to break in the mill then get a new one, I change mine when it starts running funny or hard to crank but yeah when the first coil or two stops glowing then its time for one ...check it by taking it out and touching it to the igniter but be careful as the tip will get hot fast ...compare it to a new one then you will see the diff.

IL2mSturmovik

Be patient and follow teh great advice in this thread.
2dmaxs is one of teh best though, no substitute for experience

SparkedFlyer

Ok, so I read all you guys' advice closely, revisited some tutorials and I had a much better outing today. Although, I ultimately discovered that my fuel tank was bad. The little round red rubber primer seal at the bottom of the tank was all twisted and Horizon support said that would cause the problems I was describing. They shipped me a new tank and some fuel tubing so I should see that later this week. Meanwhile, I was able to run for two tanks and it only shut off on me once and I was able to restart it after letting the engine cool for a couple of minutes in the shade. I will keep trying and hope to get the hang of it. Thanks to all for your help! I'm really glad I posted in here.

full maxx

yeah there are a lot of cool people here but for help with tricks and hop ups check lstforums.

RenegadeRevo

My Feedback: (1)

I'm considering replacing my fuel tank before I start break-in on my new Mach...

SparkedFlyer

You should Horizon support and they'll send you a new one. They didnt even ask how long I had, where I bought it, etc. They were great. They're even sending me some quality fuel tubing. Also, is it OK to prime the engine by blocking the exhaust tip and turning the engine? I saw some people priming like that. i ask because my primer pump doesn't work. It wont push fuel to through the line.

2DMaxLST!!

I never use the primer on the tank, never... I either block the exhausts or better yet blow on the pressure tubing than connects to your exhaust.

Sugafree

Same here...........

If you Do or Did try the Primer on the tank your better off to remove it as they are Know for Air Leaks........

Re-moving the Primer from LST1-LST2-AfterShock Fuel Tank

full maxx

ditto on blocking the exhaust tip