XRAY - Model racing cars

having a few problems guys... i started my nt18t for the first time today, it started well but it ran at a realy high rpm at idle, so i adjusted the idle screw till it cut out, then i turned it back a quater turn so it would keep running... but it still seems realy high!! when i put it on the floor it shoots off like the throttle is open... so i thought id just put up with slowing it down with the brakes just for the break in period so i applied a tiny ammount of brake to slow the truck and the engine cut out emideately... not sure why, i rang my lhs and they said to raise the idle rpm so that it didnt cut out, but that just made it roll even faster at idle, and the brakes still stopped the engine!!! i never thought the brakes should have an effect on the engine... just so you know, the carb doesnt move between idle and brake, so its not that...

at one point i managed to get the engine to keep running on full brake (pure fluke!) and even then when i applied the brakes the rpm went down, just not quite as low as zero lol...

all help will be very appreciated!!!

So are you saying at idle, the car still wants to move forward? Could that be your clutch spring settings?

More info we need. like How much air gap is the throttle open. If you just assembled it It has to have a hi idle for the clutch to engage. New clutch spring are tight when new.

clutch springs are my guess too, but have you tryed to look down your cab and see if it closes when you apply brake?

It seems the LSN is not set correctly

When it is set to lean it will give a high idle and it is difficult to set the idle.

First things first. Center all the sevos & linkages as per manual. The manual will show you the adjustment screws Idle speed, HSN, LSN. Get familiar with it, cuz I dont have t descibe it to you all.

The engine is set up to start for you right away. the next thing to do is the break-in procedure. And doing that, leave the car on the starter box to keep the wheels elevated.

Start the engine. Set the idle sped lower. Then The HSN to 1/8 turn to CW direction to start leaning it out.Continue with the CW HSN till you have good acell to 3/4 quaters throttle. If your idle rises , turn it down a trish. When accelleration is achieved. Start adjusting the LSN.

LSN turn slowly CW. The idle will rise, stop there. It started to get lean, Tun the idlespeed down a touch. and turn the LSN 1/8 turn CCW. At this time it wold be close to running smoothly , ADJUST THE hsn if you lean it out some more. LSN yo'll seldomly adjust cuz, it is proportional tothe HSN.

Doing the adjustment by steps will keep you from being confused. Setting idle speed first, HSN next, LSN last'

Try that! hope it helps! Adjustment done with wheel elevated. Then we'll go from there.

After all that, the fun begins. Clutch adjustment will be Found under the FAQ.s thread in the forum. Just ask there are three guys here to help, Myself , kant & mini. We'll steer you in the right direction.

Try using a 1mm allen wrench to gauge your carb opening setting.Then if the idle is too high slowly turn the low speed neddle in 1/8 increments ccw or open till the idle slows.if the idle is too slow turn the low speed neddle clockwise at 1/8 increments till the idle is to the desired sound.With 30%
nitro fuel run the highspeed neddle 3 turns out.Also check to makesure that the exhaust manifold is sealed at the exhaust port ,a vaccumn leak would give you alot of trouble like you are having.I have the picco p-0 in my nt18t and it rips.good luck.Also have you read the tuning tips in the nt18t engine manual.

thanks for all the help guy, im not quite sure where to start now, i think il try richening the lsn first, i think that might help... then il try the rest of them...

it will have to wait till tomorow though... DAMN BRITISH WEATHER!!!!

From my last post. Not getting to confusing. When you start up. your wheel turn. Lower your IDLE Speed down til they stop turn. Then the HSN & LSN as been mentioned on the first post. Idle speed, HSN, then LSN is the procedure to follow.

well thats all very good in theory, but what hapens if the wheels just dont stop, the engine cuts out first...

well have you taken off your clutch bell and checked your clutch springs yet? they are easely destroyed if you didn´t take care when installing them.

i havent done that, and as i bought the kit half built off my uncle i dont realy trust his building skills, i will not be happy if he has done it wrong.

i will check that first thing in the morning, its just a pitty you cant realy check without removing the engine...

If its dies b4 the wheels stop turning, something is binding the Clutchbell. If you remove the engine, the clutchbell should be freewheeling. Or with it not running and the throttle open manually. The car should be rolled on the ground with no resistance, back and forth. If not the clutchbell is binding.
If removing the engine , just remove the countersunk screws (4), that way you dont have to redo the mesh between the spur & pinion.

just thought id let you guys know, ive sorted most of the problems (still leaks quite a bit but i think its normal to leak a bit... i took a little video of it...