Well i finally got my lst2 broken in and my LHS offers a free tune up if you bought the car there. So i took it in yesterday and got it tuned up. They had a line there so i left it there over night. The next day i picked it up and it seemed to run...mostly accelerate...poorly. My Question. Is the mach 427 supposed to happily run rich or could i lean out the low speed to keep it from dieing on idle and bogging from acceleration if i let it sit idling for a while?

I'd never let anyone else tune an engine of mine :\

In any case, if I were you I'd return the settings to factory and re-tune to your preference.

I run a losi 427 in all my cars. It is awesome. Put the low needle where it needs to be to give a long idle and punch it. Should rev up with no bog. I run the high end slightly rich unless Im really trying to kick my buddies ass.Dont let some idiot tune your cars...alot of people claim they know alot and know not.

MY 427 really didn't start to wake up until I got about a gallon of fuel through it. I had some probs here lately but got them fixed. If I were you tune it yourself that is the only way you will get a feel for your motor. (not ever motor is the same) I would definitely take out the primer pump in the fuel take. Mine runs a lot better with out.

It depends on several things. You can observe the engine by its sound, by its temp, and how it feels to the trigger. Since you feel it is sluggish, did it used to run much better? If so, they probably tuned it too rich. Also, listen to the sound of the engine, and if you have a temp gun, check the temp and run your engine between about 250-270degreesF. Listen to the sound of your engine. When your engine is at these temps and it responds great to the trigger, memorize the sounds it makes. This is the optimum tune. If you want to go slightly richer (most advise to runs slightly richer than max performance needle settings), then tuen about am 8th turn rich from best performance tune.

To me, I am guessing your engine is not yet fully broken in and your store tuned your engine a little too rich. How many tank have you put into that engine so far? It probaly is not yet fully broken in until you het about 8-10 tanks, depending on how precise the engine was made at the factory (particularly the piston & sleeve), the break-in method you chose, the oil content of your fuel, etc.

GLK has the right idea...my losi 8t ran good but after I did my tank mod it fixed the inconsistant runs.My losi 427 engines dont require much breakin...thats why i like em. I still run them rich for about 6 tanks but the engine is not finicky like some.

Don't Forget a motor will run better than ever too lean then it will POP!!! i've made this mistake a few times in my earlear years.