New lst2 not running well

[stunt]

I picked up a brand new lst2 last Saturday. I went easy on it for the first 2 tank fulls (lots of cool down breaks after each 2-3 minutes of running). I leaned it out a bit more after each run, and it seemed to pick up a bit more power each time.

Up until this point, it would start up pretty much right away hot or cold. I have now run perhaps 4 tanks through it and now I can't get the rpms up high enough to shift into 2nd gear, even in low range. It also won't start when hot.

So I went back to the initial settings (high idle out 4 turns and low idle out 2 turns). It still won't get enough rpms to shift into 2nd and it still won't start when hot. Right now the high idle screw is perhaps 3.5 turns out and I get very little smoke (as if it is running real lean) when I get on it, either from a standstill or when accelerating. Going back to 4 turns out doesn't make a bit of difference.

I picked up an infrared temp sensor and its running at about 270 or so. Mind you this is with no body on it (max airflow), and without it even getting into 2nd gear in the low range.

When it ran the strongest it wouldn't pop the front wheels off the ground on asphalt even in the low range when flooring it from a standstill or when already at speed.

I'm in Virginia and it has been hot and humid as hell all week with temps around 100 degrees. Could that have something to do with it?

Should I just be patient with it and continue running through tanks with the high idle at 4 turns and low idle at 2 turns until I burn all the way through my 1st gallon?

I guess I'm curious how long it takes to brake in one of these things. My buddy picked up a revo 3.3 at the same time I picked up my lst2 and he is running circles around me. Both engines were broken in in the same manner (we ran them both side by side) and they both have had the same amount of fuel run through them.

Will the Mach 427 begin delivering the goods after I run some more fuel through it, or should I bust out a LRP z.28R spec3 if I want to do wheelies and be able to keep up with my buddy's revo 3.3?

 

[jon2]

Are you seeing the throttle servo open the carb all the way open? I had a similar problem and it was my battery. I had to switch to a Rechargeable RX pack and it would finally open it up all the way.

 

[stunt]

I'm pretty sure the servo opens the carb all the way. I'll pop the air filter and check just in case though. Thanks.

On a side note, the guy at the lhs said that anything between 200-300 temp wise is fine. I though anything above 240ish was bad. Perhaps that is not the case with these engines?

 

[jon2]

Temperatures are just guidelines. Traxxas says differentyl on their engines but some seem to run better near 250- 270 F. What fuel and plug are you using?

 

[chuck3]

this might not solve everything, but try a new glowplug. that tends to solve most, if not all of the problems I've ever had with my motors not running well.

 

[olds97_lss]

Your only on tank 4 and are looking for performance? I don't typically start leaning for performance until tank 10 or so. Even then I run on the rich side for the first gallon.

I just broke in my LRP28 and it ran like crap until about tank 6. I'd lean it a bit each tank after the first tank just to get it to run ok at 1/2 throttle. I didn't hit WOT until about tank 8. Even then it was just for a few seconds. I've just finished my second gallon and it screams. At about a gallon it was putting out max power and it still is.

I think your jumping the gun a bit and are expecting too much too soon.

 

[stunt]

Olds97, that makes a lot of sense. I'll run at least a gallon though it before passing judgement.

That said, I'm running "Blue Thunder Race Formular 20%" and I just changed the factory plug for a Mccoy MC-59.

Same thing as before. No smoke, no rpm to get into 2nd... It does start a lot quicker now and will even do so when hot.

Perhaps the carb got an issue? It almost seems like I'm not getting enough fuel, despite my high idle needle being way rich.

I can pop the fule line of the carb and when I hold it below floor of the fuel cell, fuel flows freely.

My intake filter also looks fine (as I would expect after only 45 minutes total running or so on the whole contraption.)

 

[chuck3]

check to see your pressure tube isnt blocked. and what type of fuel filter do you have? the factory one on the AS and LST were leaky peices of crap, I'm not sure if they fixed that on the lst2.

also, as a rule of thumb for me, clean your intake filter after every run! even if you just get a little bit of dirt and dust in it, if you dont clean it every time that little bit ads up each time.

 

[Coach Z]

I got an LST2 about a month and a half ago and had some similar issues. Started seeing real power gains as the engine got broke in properly, like 1/2 - 3/4 of a gallon into it. One thing that helped a ton with keeping the temps under control was to seal the back plate of the engine and the neck of the crankcase where the carb joins with rtv silicone. Give it some time and you'll be happy with it.

 

[stunt]

Yes, I'm using the stock fuel filter (which is pressed up against the cylinder head cooler). I took it apart and the screen is clean, but it does appear to be a poor design as the o-ring pops out if you tighten it too much.

It's starting to run better now though. I went through 3 tanks this afternoon and after the 2nd one, it easily shifts into 2nd gear in both high and low range. It will also pop a wheelie in low range in the grass now. Turns out the reason I was having issues starting it when hot was that the C battery in my ignitor was weak.

 

[olds97_lss]

Mine was leaking like a sieve when I took it out of the box. The o-ring was actually tore. Made break-in a living hell. I cleaned the entire filter with DA, removed the o-ring, loaded the threads up with RTV and screwed it back together. I let it cure overnight. No more leaking.

I've also noticed that the mach engines like to leak. I sealed a couple of my buddies engines up for them and they run much better. I just put RTV around the carb neck and the backplate after cleaning off the surfaces with DA. Both were leaking around the carb. I did the back plate just for good measure.