Xrc 1/5 Rc 23cc Engine Running Probs! - RC Groups
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Sep 06, 2007, 08:00 AM
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Xrc 1/5 Rc 23cc Engine Running Probs!

HI, im new on here, just wonderd if anyone knew about the probs im having with my cars engine. it will start ok but i cant seem to get the H/L mixtures correct. it sometimes wont even pull away, it just bogs down and stalls! i have stripped the carb down - and found nothing, i have also replaced the spark plug - but to no avail! i have the standard mixture settings in the manual but even with these it dosn't seem to want to rev very high at all. and sometimes wont even clear out. (running in is almost complete) ??? if anyone has any ideas/tips/tricks that i could apply to the engine i would be much obliged.
thanks in adance crew.
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Sep 06, 2007, 03:46 PM
34Ford's Avatar
Will it idle at all?
Does it bog when you apply the gas?

Usually if it bogs its to lean. If it takes off but starts missing its too rich.

Also check for some kinda obstruction in the muffler or pipe.
Sep 07, 2007, 11:21 PM
Registered User
I had the same problem with mine. The problem was the black hose between the carb and the fuel tank. That crappy black hose collapses very easily. It is routed under the air filter and can be easily kinked. I would start there.
If you set the H/L like the instructions said, and it boggs badly when throttling up, I would start with a fuel flow problem....

Good luck!
Jan 28, 2008, 08:57 PM
My XRC car engine have the same problem, it seems the engine is not very good.
Feb 06, 2008, 03:47 PM
Registered User
I Have Same Probs And I Find That If I Turn Choke To Half Way Point(if I Remember Right Its Straight Down) It Runs Well Although I Am Hunting Carb Settings On Here If Anyone Has Them
Feb 23, 2008, 10:32 AM
Registered User
check the carb gaskets make sure the holes line up. you can put it on backwards. make sure there are no cracks in the intake gaskets.
if the motor is old check the head gasket make sure the bolts are tight. if it is new the head bolts need retightened after a couple runs. tighten everything.

the carb screws turn all the way in and back out 1 1/2 turns start there.

sounds like a carb gasket. maybe a bad manifold. could have a cracked one.
if the motor has a vacuum leak it will not run. no power.

last thing if you got the motor to hot by running it to lean it may have burnt the piston , crack the piston ring or scuffed the cylinder.
Feb 24, 2008, 04:28 PM
Registered User
xrc-chris's Avatar
Hi im chris im new to this but ill start by saying hi to everyone. i have an xrc buggy the one everyone is talking about and i seem to be having the same problems as one of the other guys on here.everytime i try to excelerate it just keeps cutting out.after reading some of your coments on this im taking it, it is something to do with the H and L settings lol.I have all of my hand books but it doesnt say anything in there about this problem.could anyone suggest anything?????? and also does anyone know the H and L factory settings???????????

Feb 25, 2008, 03:40 AM
Registered User
typical stock motor carb settings are 1 1/2 turns form closed on H and 1 1/4 turns from closed on the low.

some info for you new guys.
in gassers, the Low needle supplies all fuel for the full rpm range.
the low needle effectively handles the rpm range from idle to about 1/3rd throatle. then the High needle then ADDS GAS to that of the low to go from 1/3rd to WOT.

it is the opposite in a nitro for those of you who have nitro experience.

a rich motor almost sounds like it is Gargleing mouthwash.
a lean motor almost sounds like its trying to push a log out after bar night, but just cant do it. lol

check the color of the spark plug porcelin (the part just under the center electrode).
the color of that area will tell you alot of how the car is running n the jetting of the carb needles.

black/dark dark brown is Rich.
darkbrown/med dark brown is a littly rich (about the color of a hersey dark chocolate bar)
Medium brown is a safe tune, not to rich, not to lean. (color of a rego hersey bar)
light brown/dark tan is also a safe tuning color ( think burnt carmel color)
medium tan/tan is performance tuned (rego kraft carmel). this is about as lean as you should run the motors, this is also typically where your circut racers are about, this get the most performance out of the motor.

light tan is getting lean. need to richen it up.

grey/white is VERY LEAN. if you dont richen it up, you ll be rebuilding the topend.

the way to check the color is to run up to 1/3rd throatle. spool up of the motor should be smooth and steady. set the low jet so the motor does this, do this while driving it, not on the bench, you need to load the engine to get realistic readings off the plug.

now once that is done, start by running a higher rpm, but hold the rpm at a steady spot for about 15 seconds. then shut the motor off ASAP. this is an important step. if you dont shut the motor off right after the 15 seconds of a steady rpm, the color will change some, and you ll not get a True reading. once the motor is off, pull the plug and look at the center porcelin and see the color (this is called reading the plug).

check the referance colors above to see where the H jet seems to be running, Dont adjust the H needle yet, just check the color. reisntall and restart, this time go a bit higher on the rpm range than the last run and do the process over and over until you get to WOT (wide open throatle). as long as the plug color stays in the safe zone (think hersey bar brown) all the way up to WOT, then run another WOT run and make any high speed adjustements to get the plug color in the safe zone.

once there, run it and have fun.

just make sure to stop the motor IMMEDIALY afterwards. what i do is put my front wheels agains a wall or such, but on dirt so the rear tires can grip but still spin. this way the kill switch is only a finger away. i have a remote kill switch i will be installing on my 5B which will help this as i can just push a button on my remote and kill the motor.

as the carb goes, the needles on walbros ( i think these have walbro carbs ) you ll see 2 screws near the top of the carb and one larger screw near the bottom.

the top left screw is the High needle marked with a small H by it, the top righ screw is the Low needle marked with a L buy it.

the large lower screw is the idle adjust screw. this only opens the carb butterfly with varries the amount of air flow at idle and thus adjust the idle.

also note, when turning the L screw, you will notice the idle change, dont confuse this with adjusting the idle cuz thats not what happening.
when you turn the l screw, your changeing the gas/air mixture, more air is more lean, thus higher idle.

also clockwise is closing (leaning) the jet. counter clockwise is opening (richening) the jet.

if the motor is idleing, and the idle is erratic and not steady, you have an air leak. an air leak lets in more air, thus makes the motor lean.

if your using choke to keep the motor running, its time to tear into the motor and look for an air leak. usually found at the carb manifold or gasket. but can also be from a loose cylinder or blown cylinder gasket.

the coil may need to be adjusted for proper coil/flywheel gap. a standard business card works very well for a quick cheap measure. loosen the coil, slip the business carb between the coil and the flat spot on the flywheel. push coil snug to flywheel and retighten coil mounting bolts.

if the motor is new, then you may be experinceing a fouling or fouled plug. typically if the motor starts and runs the plug is not fouled, but maybe close to being fouled out. replace the spark plug with a new one, if its still haveing the same syptoms, it time to start looking elsewhere.

from my understanding the XRC motors are cheaper copies of the cy motors, which is a lesser expensive copy of a Zenoah motor.
dont have or havent seen, dinked with an XRC, so i cant offer much more.

one last thing, a new plug will take a bit of running time to develop a readable color. when your using a new plug and are unsure of your needle settings, keep it rich until the plug has some color to it.
and yes a dark plug color will lighten up in color with adjusting the needles.
Last edited by Timmahh; Feb 25, 2008 at 03:48 AM.
Feb 25, 2008, 08:16 AM
RTF copters maker
maximus-rc's Avatar
Hi all !
I am distributor of XRC buggies in France.
I post the reply of manufacturer hope this will help you !

For the adjust of the crews as follows, wish it will be clear with you.
Carburetor Adjustment
H Mixture Ratio
L Fuel Delivery
Adjust both of them together, make sure the engine can upto maximum no load governed speed and the idling is stable
Adjusted Methord
H Screw down the H tightly and then pull out this screw between 1+1/2 and 1+3/4 circle
L Screw down the L tightly and then pull out this screw between 1+1/4 and 1+1/2 circle

They also told me that they have "improved lots parts" and "also we have speedup engine, it can upto 19000rmp - the speed about 80km/h"

Feb 25, 2008, 12:19 PM
Registered User
Maximus, can you confirm what Carborator is on these? it is indeed a Walbro?

seems alot of folks are having this very issue. lets hope they improved the motor to be better running. 19000 RPMS dont mean squat if the motors dont run.
Feb 25, 2008, 02:50 PM
Registered User
xrc-chris's Avatar
thanks everyone that information was great especially Timmahh i will try out the things you said about the plug.ill have to print it of and go through it step by step.

when i run my xrc buggy i have to run it with half choke or sometimes full. why is this ??? i know one of the other guys said it might be an air leak or somethin or a gasket. does anyone know more about this ???

Feb 25, 2008, 03:02 PM
Registered User
if your choking it to keep it running, thats a sign of somthing is amiss.

how does it idle when you first start it? smooth and steady, or is it all over the place, like your squeezing the throatle but arnt?
if its all over the place, then you have an airleak somewhere.

to find an air leak i ll get the motor running and warmed up. once it is warm, then take a can of WD 40, and spray the wd around the gasket areas. dont give it a lil squirt, spary it like your painting with is. if there is an airleak going on somewhere, then the RPMs will change (typicaly drop down) when the WD hits the air leak area.
once you find an air leak, you have to pull the parts off and correct the issue. sometimes its only tightening up a bolt or two, other times its a new gasket or more.
just depends on where the leak is at.
Feb 27, 2008, 04:23 PM
Registered User
xrc-chris's Avatar
well ill start it up and it will just tick over normal. it doesnt keep reving uncontrolably. i always have to give it at least half to 3/4 choke everytime i start it and leave it there cous if i turn the choke off it just die's.? iv reset the H and L settings now cous i thought it might be something to do with that.as i am an amature i dont realy know much about it so your help is much appreciated Timmahh and everyone else who has helped me.iv took all the carb of and the black plastic from under neith it and checked the gaskets and they seem fine. no crackes or defaults in them. could this be caused by something else do you think ???????????.

it takes me about 3 pulls to start it affter that it runns reasonabley well.

as i said i had reset the H and L settings but im still having the same problem it is still dieing everytime i pull the throtle back?????

help lol
Feb 27, 2008, 05:28 PM
Registered User
so you still have to have the choke on to keep it running?

what happens when you take the choke off it just dies?

sounds like a carb problem if the needles are at stock settings and it still needs the chock to run. either that or you have a fuel delivery issue.

loosen up the gas cap on the tankd, then try to start it and see if you need the choke to keep it running. but with what info you have posted. im leaning toward a carb issue.
Feb 28, 2008, 11:49 AM
Registered User
xrc-chris's Avatar
yeh as i say it just die's when i turn the choke of witch i thought was rather strange.ill try loosening the cap on the fule cap. but if i have a fule delivery problem how would i test that Timmahh.

thanks for your help by the way realy appreciate it mate.

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