gonna sticky this again?

thanks jeremy

sent you a pm. yes it will by monday when everything gets sorted out..

is this with every engine ? i though you set the idle than do the main needle than the low end needle ?

i run a rb hobby 9 (s5 ) sport engine.

This is for Go based engines with long LSN but can be used with short too if you know it well.

i have ALWAYS tuned my engines this way(whatever the BRAND is) except OS i have NEVER tuned an os

Am i right in thinking that as long as the revs rises slightly when doing the pinch test when fully warm, that the lsn is set slightly on the rich side or even ideal? Or is this just that you have set the idle gap correctly?

If an engine has a 2 stage idle (high the low) is that indicative of a rich lsn?

Sorry for the umpteen questions its just that everytime i get it right in my head i reread the entire thread and start second guessing.

Thanks

The pinch test is for the LSN and the idle gap. How high it revs is idle gap. Should only rev up slightly, like 500 rpm's. How long it revs is rich or lean. Should be about 7 secs. on the long LSN's, 4 or 5 on the shorts. Also should be done with a warm engine, not a hot one. I believe this is correct but sometimes I dyslexic so you may want to wait on a confirmation on this.

correct

Well yes and no. 7 seconds is an average for the Go carbs. Nova based carbs you want a 10 to 12 second pinch. same with OS carbs. So it depends on the carb and the needle jeting and taper angle.

What is best to do no matter what carb you have is tune the LSN and idle gap first before you do the HSN. If youre not sure of the LSN pinch time go for 10 seconds to be safe.

What pinching does is lean the LSN setting to un mask the true idle gap setting. then once thats sorted the HSN can be tuned and then you may re visit the LSN and idle for a finer tune as the HSN will effect the LSN setting.

the times given EG 7 or 10 seconds takes into account variation in heat and HSN settings. once that all sorted and the engine is hot you will find the LSN setting has decreased down to about 2 to 3 seconds which is safe.

Remember when you get lean bog at any time ( usually at half tank ) richen the HSN .. NOT the LSN ..

MM

Does anyone have this is a pdf or word doc?

You dont need a tuning guide you have a Derek. LOL

This method will work on your OS carbs really well though.

http://www.rctech.net/forum/8075559-post1.html

on the front page for you guys

What ideal pinch test on Os engines? Specificlly a 18tz.

Hello, i have a GO 21-5port nitro engine. When there is 10-20% Nitro fuel left in the fuel tank the engine performance is much better then when there is much fuel in the tank. Can someone tell me why? Shall i lean the needles or do i have airleaks, can the lengt of the fuel line have something to do with this? I want the engine to run like it does with little fuel all the time.
/Regards Peter

yes, you are a tad rich on top..but only lean in 1 hour increments....meaning if the needle was a clock, only adjust 1 hour at a time......the Go high speed needle is VERY touchy....but once you get it dialed, it will GO