Tuning Problem or Airleak?
 

When started, the car idles and revs fine.

However after a few mins of running and the engine has heated up.. WHen i rev it, it rev off its nuts and doesnt drop back down for a few seconds..

Im thinking it was a LSN problem.. but LSN is on stock setting.. maybe the HSN is too lean? can that cause it?

try to rich the LSN
sounds a bit lean

at the moment im using these settings from the novarossi site

High Speed Needle - 5 turns from closed
Low Speed Needle - 2.5 turns from closed

although im using a old school novarossi sx-12.. dont know if those settings still apply

ill try using start tuning LSN from 3 turns out,

ur low end is too lean... therefore try to rich abit and try... at the same time check ur idle hold opening.

Factory settings on the older Nova .12's was often a bit on the lean side. Richen that bottom up a tad and see if it helps.

To add to this, with the engine stopped, remove the air filter and check your throttle endpoint settings as well. Look inside the carb as you move the throttle back and forth with the transmitter to make sure you're not have any issues with servo movement.

ill have another go tonight. ill try turning the lsn to 3 turns out, it it all goes ok, ill start tuning it from there.

there is no servo movement, i checked that when i ran it yesterday cause thats what i thought was causing the problem.

still cant figure it out..
LSN is about 4-4.5 turns out.. still takes off good though, but still making the noise after its heated up and i rev it.

servo is not moving, i took off the air filter to check.

also i cant hear it shift.. can overrevving a engine cause the problem?

how big is ur idle hole? and what plug u using?

idle hole is tiny!!.. bout 2mm not even, its pretty much almsot closed.

using a rb6 with 16% nitro.

im absolutely lost on what to do.. i cant figure out anything!

Only so much help we can offer over the internet. You may have to seek help from another racer on your end...

The only other things that I can think of are:

- Replace your hoses
- Disassemble and inspect the carb
- Make sure your fuel tank gasket is good
- Make sure your carb is seated properly and not loose
- Make sure your engine isn't leaking around the glow plug

Sorry, can't think of much else..

Good luck. :)

.. And check to make sure your exhaust gasket isn't ripped. That got me more than a few times...:sneaky:

2mm is huge. Should only be about .9-1.0mm

id check that, but im pretty certain that all the above is fine!

iv been innto nitro rc for 4 years and never experienced this.

it idles and revs up fine.. only when i let go of the throttle the revs doesnt drop.

When it does this, come in to the pits and stop. Just let it idle and see what happens.

If the idle stays high and then stalls and is difficult or impossible to restart until it cools off a bit, it's probably vapor locking. Temps are too high, richen it up.

If it stays high for a bit, then comes down to a normal idle and seems fine, there are two main possibilities.

1. The LSN is too lean, richen it more.

2. The idle is set too high. With it at that high idle, back off the idle screw until it comes down to a normal idle. It will probably want to stall then because the LSN is way too rich now. Lean the LSN until it idles right again.