Outer Limits 4x4 Board

hi guys ive got a 95 lux RN105 petrol carby and when i start it wen its cold the revs go up to 2 grand straight away an then climb to 3.5 grand and sits on that till the engine warms up.i disconnected the auto choke (cut the red wire) and it hasnt done anything.could it just need a carby kit(new seals etc)?or could it be something else like maybe just adjustment of the fuel mixing screw or something?any help would be great its driving me nuts.cheers

having a 22r myself i cannot say i have had this issue, though i once had a situation where it would only run at full throttle, as the jets were old and blocked etc.

have you tried starting it then giving it a stab of the throttle or even a decent rev? because mine used to idle high when cold but not way high, with a bit f a rev, say to 2500revs it would go back to usual idle.

Just take it to a mechanic and tell them whats up, to get new jets and seals in my carby it was less than 200 im pretty sure. but well worth it, and its a very simple engine, so its not like it could be anything major.

yeh tryed having a stab at the pedal but doesnt do anything.i have had alot of dodgy experienceses with dodgy mechanics so i try avoid them as much as possible.thanks for ur help

think its just a warm up mate, petrols do it, start it in the morning when its still cold 6am, then let it run for about 10 mins it will either drop. or just rev it a lill and it should go down,

does it do it when u stop at traffic lights?

banks001 wrote:think its just a warm up mate, petrols do it, start it in the morning when its still cold 6am, then let it run for about 10 mins it will either drop. or just rev it a lill and it should go down,

does it do it when u stop at traffic lights?

yeh i just dont remember it always doing it and with the choke being disconnected i wonder wats causing it.wen i drive it wen its cold the revs go down but go back up everytime u put ur foot on the clutch then wen u let ur clutch out at 3000 revs its not nice but as i said wen its warm it sits at a grand and idles smooth

hmmm ill run it buy my mate who is a mechanic but in the mean time,

just pull up to ultratune or somewhere and just tell them the deal they should be able to tell u right there wat the problem is, then u can go aorund gettting quotes or fix it urself

Check the carbie is bolted down properly (or the gasket is sealing properly for that matter), could be sucking in air when cold and as it warms up the gap closes up. Doesn't take much. Could even be as simple as a vacuum line left/broken off but I doubt it. Squirt some crc/wd40 around the intake manifold to head gasket and base of the carbie, the revs should raise a bit if there's a leak.

As BadMav said, it does sound like an air leak. try blocking some of the air intake on the air cleaner (if you can) and see if the revs drop, then try blocking it completely, if it still runs you have an air leak. Maybe be needle and seat stuck, I recall the old holden single barrel stromberg carbies used to do this quite a lot, the fix was to tap the side of it with a screw driver handle (so you didn't break the carb) and this dislodged any crap in the needle and seat. Might be worth trying that...... Also could be the auto choke stuck, hence cutting the wire did nothing. Try loosening the three (I think) screws that hold the choke housing (usually round black and bakalite) and turning it to see if the revs drop or increase..... If you can post pics of carby that would help with diagnosis.....

That wire you cut helps to heat the coil up in the inside of the auto choke. This disengages the choke earlier, dropping the engine revs quicker.
I also agree it sound like an air leak somewhere. spray some wd 40 around the base of carby and manifold and listen for changes in engine revs. When change in revs occur thats where you have an air leak.