flat spot

[unsavagable]

Hey gang, I am in need of some advice. I own a savage and have just upgraded to a Picco .26. I live in Phoenix so I also put on a Nova head after break in. I am still in the tuning stages and am experiencing a situation where the motor acts like it wants to stall right off of idle when I give it gas, then after like .5 seconds it comes back to life and takes off. It reminds me of the days when my holley carb had a bad acceloretor pump in my high school hot rod.....I keep trying to lean out the LSN but don't feel like I'm getting the proper results. I'm running trinity 20% fuel have a dual tank mod, big joes and a 3 shoe clutch on a 16t cb. I am not experiencing wheelies yet but mabye since I have extended tvp's that wont be happening??? I'm very new to the nitro hobby and so far feel like I have had more money than sense in this hobby. But I do read a lot of these posts and they have brought me far. I would appreciate any of your feed back from you long time pros and or anyone that has an opinion, speak up please, I'm approaching desparation!

 

[Lason]

Christian pointed something out to me a while back about the Picco .26's. Take your needles out and check for debris. I had hell breaking mine in because one minute it would run awsome then get hot so I richened it up and it got hotter? Turned out I had rubber debris in the needles and when I turned the needles out the debris got lodged in the carb even more. After cleaning the needles This thing hauled much ass and runs 250-260 all day in the humid and hot Texas weather.

 

[unsavagable]

Yep, I'm aware of that issue and have taken the carb apart (twice). Found debris both times! I have also sealed the motor with silicone. I did observe the heat issue that others were experiencing (while oring debris was present). That seems to be gone and the motor does make the truck haul major but. I just would like to get it to run reliably. It stalls at random and is real intermitent off idle. What are you guys setting your lsn at (how many turns from bottom?). Remember, I live in Phoenix, hot hot hot and dry dry dry. Any other of you people ever have this happen?

 

[pissant]

ok i have not done anything yet, but i heard turn lsn flush and turn 1.5 turns clockwise!

 

[olds97_lss]

You might want to check your inline filter(s) for debris as well and maybe a hole in a fuel line somewhere. An air leak anywhere on these things creates many eratic problems.

Fuel line is cheap, so if in doubt, replace it. You also might want to check both of your dual tanks for leaks. It may not be a bad idea to re-route the fuel lines and only use one tank until you get the problems resolved. That way you can cancel out half the source for air leaks if they exist.

 

[lykan]

Sounds to me like your LSN is too lean. If it will idle all day long then most likely your lean on the low end.

After a minute or so it should load up and die.

Did you try the pinch test? pinch the fuel line to cut off fuel flow. If you cannot pinch it tight enough do it with a a pair of pliers (carefull).

When pinching if...
It dies right off the batt (1 sec ror less) it is lean.
If it speeds up for 7 seconds or more, it is too rich.

If it speeds up, and dies between 5 and 3 seconds your pretty close. Also remember on some engines 1/16th of a turn on the LSN means the difference between a crap tune, and a good one.

Sometimes I don't realize how far I turn the needle when I am in a hurry I think 16th but actually moved 1/4

Gluck, and do let us know if you solve it.

 

[StrechM]

There are several threads from last year on the performance of the Picco .26 engines. If you are still having bad results after trying the above mentioned then you may want to try a tank of 30%. For some reason the Picco .26's will run better. It will also cure idling problems if they start to develope. I suggested this to a friend a week ago and it worked,... again. Some of the old threads also mention carb issues and 30% nitro content for the fix.