Picco Micromotomori Bigga Headache

[Stroytika]

a couple months ago a meandered into my hobby shop and asked them if there was a way to get more power out of my t-maxx. They said of course, and put a shiny new picco .26 max in front of me, which i proceded to buy, take home, laugh about, and drool thinking about until i had it installed. then the troubles began.
The short story is that it loads up with fuel like freakin' crazy.
The long story is as follows.
while trying to break it in it would not stay running for more than a few seconds. at this point the setup was a picco .26 max in a 4908 t maxx with a stock manifold and a traxxas resonator. i eventually got it to run smooth by detatching the pressure line from the tank. the reason it was quitting was that it would vapor lock from overloading with fuel. i did eventually get through break in with good temps and everything (i use a temp gun, so i didnt cook it, and i always had smoke)
so the problems of it quitting continued over and over from it bogging up on fuel. the next thing that i tried replacing was the fuel tank. i put on another stock traxxas fuel tank (new) thinking the problem was there. that did not stop the issue.
the next thing i tried was drilling out the stinger on the resonator, because i thought that it may have been far too restrictive. on a side note, the performance of the motor at this point was (and still is) poor. this did not help.
The next thing that i did was to cut the pressure line, and put in some antenna tube to reduce the back pressure. this helped a bit, in that it would at least keep running. by this point the load up has already cause front bearing leakage.
the next thing i tried was a Hpi savage manifold on the resonator pipe. this improved performance but didnt fix the problem. the next thing i tried to fix it was was replacing the resonator with an ofna 053 pipe. that did not help resolve the problem. but it does sound cool now =)
throughout all of this fuel economy has been so terrible because I've poured much of it out from vapor lock and that when it is running it spews raw fuel out of the pipe.
throughout all of this trying to start the motor while it was full of fuel, or just didnt want to go, i have blown 2 ez starts, 2 pull starts, and a tiger drive (including 3 one way bearings).
when i first bring the truck out, it will tire right up, then after i run it around, it will just quit because of overloading, and i can't even get it started again.
The final thing i tried was putting a pro-line runtime tank on the truck and that made the problem worse. so i did what anyone would do at this point. I emailed ofna. they brought me through checking a bunch of things. they are as follows

Low speed//high speed settings.
high speed housing being loose
proper fuel
return line location on 053 pipe (ruled out as issues pre-date pipe)
after that he was at a loss.
so basically, i ask you nitro gurus. what the Hell is up with this picco .26 max?

 

[Extreme RC Mods]

If it's running that rich I would lean the needles out. I may be wrong and am not trying to be crass but it sounds like you did everything but lean the needles out. Forget what the manual says about needle settings and adjust the engine for what it wants. Lean out the LSN until it will idle fine and does not load up. I would shoot for a .5mm-1mm idle gap and then tune around it, once it's set it shouldn't need to be touched again. Once the performance starts to come up with the tune, you can continue to performance tune it like in my guide below. If this doesn't help, let us know.

 

[mr73cj5]

make sure your fuel line is routed so it is higher than the top of the tank. this is a design flaw with the t maxx tank. if the fuel line is not higher than the top of the tank the fuel will siphon out of the tank and cause the engine to flood and also cause all sorts of tuning issues. hope this helps... good luck
Mark

 

[Stroytika]

thanks for the replies guys. good advice, especially the tank.
my picco seems to have a silver low speed needle. i dug up some stuff that shows that this motor should have a different, black one.
http://www.nitrohouse.com/Engine-Pa...EDLE,-LOW-END,-MAX-21,&-12R/product_info.html
i found old posts on this issue with the picco .26, and it is very obvious the wrong low speed was shipped with the motor.
the real question is could the wrong low speed needle cause all of these problems? i also know the webpage says its for the 21r but going off the parts diagram i have thats the right low speed. i'm sure the one on the web link is the right one.

 

[Extreme RC Mods]

That is the blunt needle, your tune needs to be a little more precise apposed to the tapered silver one. I would try leaning the LSN until it will idle. If the level of the tank is higher then the carb inlet, I would try only filling it 1/3, prime it just before your ready to run and then run the engine for a bit and give it a chance to build some heat first. Then fill the tank and go for it, picco's do not like to run cool, lean it out and get the temps over 200F before you really try to put a tune on it. You can try the other needle, they have been using the same style ever since those .26's had the problems.