Help... i got a new nitro rc monster truck- just finished break in (fine-no probs)when idle goes up and car moves at walking pace at no throttle, so I turned down the idle then it was choking or stalling on acceleration.... last time it stalled it wouldn't start... then I started fiddling and made things worse 馃槧
It will run for a few seconds when i put a few drops of fuel in the air filtre hole, I primed it by blowing in the exhaust hose and removed air from the hoses, glow plug works???
Question 1: can fuel gum up over night in the carby? If so how do i fix this (cause it seems fuel wont flow)
Question 2: does any one know the base screw settings to get me started on a .18 cxp engine. eg how many turns out from closed on the low/high speed and idle screws.
Sorry this has nothing to do with vw's but im in desp. need
(have to beat a mate tommorrow LOL)
zac_smits 路
what type (name) and brand.
i have a tamiya mercedes c-class road racer with a .15engine
and a tamiya bison 4x4 with a .40 nitro engine.
the majority of the settings are stated in the maunal..
Untermensch 路
I got a nitro Schumacher Fusion.
Awesome bit of gear.
tassupervee 路
1: Gum up the carb overnight, nah, not likely.
2: Base settings? Well if you dont have any documentation with the car on the engine a loose rule of thimb is 2 full turns out on both adjuster screws/needles.
OK
If youve not played much with glow plug engines before.
Whenever making carb adjustments, alway make a note of how many turns (or parts of turns) you make to a particular adjustment.
Always make very small adjustments, no more that 1/8 of a turn at a time either way.
Always make your slow run adjustments FIRST and high speed adjustments second.
Reason is that the slow run adjustment influences mixtures right across the range but high speed adjustments only affect high speed! Its a common feature with almost EVERY carb, not just an RC engine.
Its probably a bit late now but its a rule of thimb for beginner engine tweakers!
Since the car was going ok enough before you fiddled but was stumbling on throttle opening, then the slow run adjustment was a bit too lean.
About 1/8 turn out on the slow run setting would have dealt with that.
K, the engine will only run for a few seconds with fuel dripped into the carb.
Too lean.
Since ALL the fuel to the engine must pass thru the slow run needle before it can feed the high speed needle, your slow run needle is wound wayy too far in.
I would suggest turning it (slow run needle) OUT 1 full turn from where it is.
DONT touch the high speed adjustment just yet.
It should now (hopefully) run better but may require further adjustment out if the engine runs real clean and slows down and dies, particularly after touching the throttle.
Turn the adjustment IN (lean) by 1/8 of a turn and try again.
Just keep playing with it until you get the fastest and smoothest slow run.
After this, turn it out a poofteenth RICH. Just enough to notice the engine running a bees dick slower and rougher....just a poofteenth K.
If at first it runs slowly and roughly with plenty blue smoke but responds to throttle opening, then you are too rich. Do the opposite of above.
K, now the engine should be idleing happily and it will respond to throttle.
Set your throttle stop (idle speed) to the highest speed the engine will go without the car pissing off, just so the car is creeping along a bit at idle and needs the brake to hold it.
This is a good time to check your slow run mixtures again. Make TINY adjustment untill you get maximum idle speed and then richen it up just a tiny bit.
Open the throttle suddenly, If it stumbles and dies almost immediately like sort of switched off, you need to turn OUT the high speed mixture 1/4 turn RICHER
Throttle it up again and repeat the adjustment untill the engine will accellerate some then start blubbering unevenly and smoking which means it is wayy too rich.
Now, turn the high speed adjustment IN by say 1/8 of a turn at a time untill the thing will scream its bloody head off.
If at first the engine immediately blubbers and smokes to a stop then it is too rich and so do thew opposite of above, lean it a bit and try again.
Righto, stick it on the ground and snap the throttle open and let it go flat out to max revs.
What you need to do hear is listen to the engine and if it screams really cleanly and never blubbers or "4" strokes, bring it back and adjust the high speed adjustment OUT (richer) so the engine will "JUST" begin to blubber at all-out maximum revs.
This will give you the most reliable idle and accelleration of the engine and should prevent the engine from "gasping" with sudden throttle openings.
Once you get the hang of it, try tuning the main mixture tiny bits leaner untill you get the maximum revs and accelleration out of it.
However, always keep the tuning JUST short of blubbering and smoky (rich) to keep the combustion temp;s down and reduce the chances of a seizure.
Remember, ANY adjustment you make to the slow run mixture will have a corresponding effect on the high speed mixture.
So if you clean up (lean off) the idle a bit, you need to richen up the high speed adjustment a bit to compensate.
Once you get the thing correct, you can pretty much forget the high speed adjustment and simply make a global mixture adjustment to the slow run adjustment.
Happy RC'ing dude
L8tr
E
Untermensch 路
What he said.
Mad Manx 路
Firstly thanks tassupervee thats a wealth of knowledge you have.
While offline (before reading this) I removed the carby and took out the needle valve and cleened the carb out.... when I put it all back together it start enough for me to correctly tune it - goes now like its never gone before, unfortunatly I got carried away and during a roll over the reciever got switch off (I have a fail safe I installed but its no good with out power) and the mongrel think went straight for a fence post.
Broke the bloody axle holder/steering arm in half.... I guess this is one of the joys of the rc world hey