carbon fouling

[jonnyshaw49]

hi i am currently finishing my r5 gt project and the car is sat in the garage since having a full rebuild, the car had all new piston liners and rings all bottom end done then set up on rolling road since then i had the head rebuilt and ported and polished but because the car is sorn couldnt have the carb set back up. i havnt run the car for 2 weeks and have recently fitted new alloy rad and oil cooler and come to start it and it just wont, it is firing but wont start, i took the plugs out ngk b8evx and looking at them compared to sprak plug guide there dry, black and sooty, this said carbon fouling due to over rich fuel mixture. is there any way i can adjust this by myself at home just so it it running ok untill i get it finished to go and get it back set up. everytime i started the car since the headwork it needed alot of choke to get going and wouldnt idle untill warm,what is the best fuel to use?has anyone got any ideas???? just going to get a pair of b8evx platinums and fuel up see if i can get it goin thanks

[Matt Cole]

Clean them and refit. Try to start it. If it nearly fires, take them out and clean again. Sometimes it can take a good few cleans of the plugs post rebuild if it hasnt ran for a while or doesnt start first go.

[Scoff]

Throw them away, fit a set of standard n/a plugs (NY9C, etc) and it'll run. They won't foul like the B8, then set the fueling up when you next get chance. Fit some new B8's in the future.

[jonnyshaw49]

hi i have filled up with bp ultimate fuel today and cleaned the plugs the car continuosly tries to fire but just wont start any ideas, i rang local car shop for ny9c plugs they had never heard of them. any ideas

[Scoff]

all the halfords used to have champion ny9c or n9ycc, or just buy whatever plug they list these days for any of the n/a 1108 or 1397cc engines. cheap as you like usually. alternitevly find youself the original GTT plugs, any of the following NGK's will be close: N2G, N2C, N3G, N3C.

If you've had the head off, check that you havn't mis-aligned the distributor drive, HT leads and so on.

[jonnyshaw49]

hi i rang back car shop with them numbers he said champion ny9cc is equivalent to ngk bp6es so he can get me these in for tomorrow are they ok to use? is it worth rebuilding the carb aswell before putting it back together. the head work was done months ago and fitted and its ran everyweek since, just wont idle untill warm so have to keep choke on, could rich mixture have anything to do with that? its only been the last 2 week it wont start i thought fuel was just low but ive put soem in and cleaned plugs but still wont start ill put in the new plugs and try tomorrow if if still doesnt start where should i be looking??thanks

[Scoff]

yes, the bp6es is another I should have mentioned, they'll be fine. they'll be fine to leave in too, unless you're planning on making a lot of power.

[Rob@Backyardracing]

surely you could just open the gap to help for now?? save cocking around...

[jonnyshaw49]

ok il get the bp6es for now im wanting to get near to 200 bhp eventually so ill just change bk to the b8evx platinum later once its set up. i have a funny feeling its not just the plugs. its trying to fire over and over again but not start then u can smell fuel like its flooding so take plugs out and un flood it but then put them back in and its same again. the plugs are black and dry, ill try the new plugs tomorrow and see what happens. if not where should first place to be start looking, like i say it was running fine other week and now just wont start. im looking at rebuilding carb has i have done everything else bar this, are they easy enough 2 do i have 2 spare ones so going to see if any have been modified on the venturi and rebuild that as it will help with the flow.

[Scoff]

It sounds like its just very rich at cranking, try starting without the choke.

[jonnyshaw49]

i did that but no joy ill try agin with the plugs in, shall i turn the mixture screw down abit, would an air leak have anything to do with it not starting, aslo any way of tellin is renix unit is nackerd??

[jonnyshaw49]

the plugs are in today so going to put them in later, had a closer look at the car this morning andalso at my 2 spare carbs all of them have number 25 stamped on the venturi so is this standard 25mm i have been lookin on here at group a carbs are they a no no, i am ordering a carb refurb kit, ebay seems to be cheapest from fastroad car, some of the kits dont supply the shaft seals are these needed or can old ones be used. could anyone tell me what jets i should order aswell, i have ported and polished head and also have a t2/t25 turbo think it could be a ktec 180, i am wanting to achieve around 200 bhp eventually and get a t25 beginning of nxt year. i also took the intercooler pipes off the turbo today and noticed in the front propperor tunnel and the tunnel coming out to the right of the intercooler it is covered in a black oily substance, this wasnt there after rebuild when we put iot back together as i put the turbo on off my other car. the car has only been run in the garage weekly, what is this? the turbo has no play what so ever, is it a breathing problem??could this have soemthing top do with the runnin problems thanks

[jonnyshaw49]

having a nightmare today lol, bought the bp6es plug fitted them and it fired first time, ran the car till warm got water bled up then turned the car off, came to start again and wouldnt, took plugs out because thought flooded could smell fuel and they were same again black wiped them off an put them back in still no joy, then noticed my mixture jet had blown out, couldnt find it newhere, so nicked one out of another carb i had and it then started. however the car just wont idle right when it was cold i got it to run at 1000 rpm let it warm up and then i revvd the engine to see if it was smooth power and wasnt pinking, it was smooth and didnt pink but when let revvs off it conked out. started again and now runs really lumpy and cant get it right at all. this might because now the engine warm. any ideas? what mixture jet should i buy? could it because the other jet out of other carb is different appreciate any help as i feel like driving it off a cliff now lol

[Markey Mark (BD)]

All mixture screws are all the same so that won't be a problem, it does have to be a specific position though depending on what your carb is like. Have you checked and cleaned the idle jet also (big brass screw on drivers side of carb), give that a good clean out.

By the sounds of it the cars over fueling loads and needs to be looked at.

Also refering to your previous post, there's no specific sizes jets for a specific sengine set up. Every car is different and requires a differently set up carb. Best thing is to get an AFR guage onto the car, take it for a drive and see what the fueling is like then make the neccessary changes to the carb jets if needed.

[jonnyshaw49]

ok thanks ill clean them out and give it a try,the big brass screw on drivers side is the idle jet isnt it says in james5 technical file, what could be the reason for loads of overfueling?? thanks

[Markey Mark (BD)]

ok thanks ill clean them out and give it a try, what could be the reason for loads of overfueling?? thanks

Wrongly set up carb

[jonnyshaw49]

i have cleaned the big brass screw at drivers side of carb same thing happens runs gets warm, revv cuts out then runs lumpy , any ideas what else to check?? how do i set the mixture screw i looked at haynes manual but cant work it out and when i screw my mixture screw nothing reall happens screw it in and its lumpy screw it out and its lumpy .

[Markey Mark (BD)]

To be honest sounds like the carb could do with a good going over, i see you have said your getting a carb refurb kit which is a good idea.

When you put the mixtire screw in how far down did you screw it in?

[Scoff]

I might be thinking of a different car so this may be non applicable, but if I remember right that car had idleing issues when I knew it. I remember there being a big idle jet in it, but swapping to a standard made it too lean. He did not want to pay me to investigate further so nothing more happened.

Swap the idle jet with one from a spare carb - it's the brass/silver bullet like jet that is pushed into the front of the big brass screw, drivers side. be carefull as you remove it, the torpedo-like piece of brass may want to fall out with it.

[Scoff]

re the mixture screw, wind it right out to begin with. once it's warm and idleing OK, wind it in until rpm starts to drop off, then wind it back out a little so that it's running smoothly again.

also check that the rubber O-ring on the screw you installed is intact. air getting past this screw will make it run lean and rough.

[jonnyshaw49]

ok ill try that thanks, so is it behind the big brass screw or par of it??? ill do that now, it never used to idle bad when i got the car so this mite have been sorted id love someone who knew bout 5 to look at the car but no one round here knows bout them and its not mobile.

[jonnyshaw49]

swopped the idle jet from a different carb, on my car on the car and one of the others the idle jet had a 45 stamped on it and another with 44 stamped on it is this standard? i fit that and it wouldnt even start and batt went flat so will have to try again tomorrow.

[TrixNFlix]

Is the accelerater pump diaphram ok and the emulsion tube clear? ? Mine used to have similar problems to you. Turns out the diaphram was torn, so leaking slightly and the emulsion tube was full of gunk and wasnt spraying the fuel into the venturi, more like a tap drip which made it a nightmare to start, and would flood alot. regards andy

[jonnyshaw49]

what size is a standard idle jet?? what size jets should i be running with t2/t25 turbo and head work??? could it be the jets are wrong size. when i did the mixture screw i checked how many times from fully in it was on the other carb i counted six full turns out from fully wound in, i did this on the carb on the car and it ran from starting ok but once i pressed the accelerator revvs wud drop suddenly before rising and then when let accelerator off just cut out. then when started again ran lumpy and wouldnt run on idle untill cold again cant work it out.

[Matt Cole]

Put the spare carb on you have and try that.

[Jonny5]

Apart from your other problems i would say that one that could be a possibility is your acc jet is loose, the big brass jet with black o ring under it that is located in fuel bowl. Mine had hesitation problems at idle an this was the cause. Was rattling in its threads lose at bottom of bowl, also make sure the acc pump arm is set to 5mm throttle opening using drill bit method. Def needs carb overhaul an get car running nice before even thinking bout changing jets.

[jonnyshaw49]

thanks for that whats the drill bit method ill give it a try tomorrow is there a thread on here showing how to set the arm, thanks

[jonnyshaw49]

i took the carb off today and tipped it upside down it was absolutely gull with fuel came out of lobster. i put the other carb on i have and it started first time but just cudnt get it to idle.the idle jet had 45 on it and swopped this for the other idle jet i had with 44 on it and i got it to idle messing with the mixture jet. it now wont run on idle when cold whatsoever. i have to put choke on at 2000 rpm wont run less than this. when temp needle is half way it will run at idle on its own at 1000 rpm. then when u rev the car and let off it hunts at about 800 rpm for a minute or two then lifts back to 1000 rpm but its abit lumpy any ideas? what shud i look at on the carb i took off ive orderd a gasket set so will build up carb when it comes. can anyone suggest what to do to get car idling shud a gt idle when cold??? never seen this lol

[TrixNFlix]

Remeber this isn't a new car with built in automatic choke. This sounds ok to me. Its quite cold today, especialy up in that their nelson! Wait till it gets colder, takes longer to settle down. Anywhere round 1000 once warmed up is pretty good. Might just need a little adjusting once warm on the idle jet screw.

[jonnyshaw49]

just stripped the carb to check the jets

main jet 120 looked slightly blocked aganst light cleaned it(could this haveomethingto do with running issues)

idle jet has 45 stampd on it

jet in bowl above main jet with ballbearing in it has no stamp

jet above venturi has 25 stamp on it

diapragm at driversside of carb with arm connected to butterfy valve for throttle intact

jet in passenger side of carb where over flow is, is stuck in cant get it out with little screwdriver

diapragms in pasenger side of carb both look intact

do these jet sizes mean its all standard, anyideas wy over fueling whats the accelerator arm and 5mm drill bit method to set it

[TrixNFlix]

just stripped the carb to check the jets

main jet 120 looked slightly blocked aganst light cleaned it(could this haveomethingto do with running issues)

idle jet has 45 stampd on it

jet in bowl above main jet with ballbearing in it has no stamp

jet above venturi has 25 stamp on it

diapragm at driversside of carb with arm connected to butterfy valve for throttle intact

jet in passenger side of carb where over flow is, is stuck in cant get it out with little screwdriver

diapragms in pasenger side of carb both look intact

do these jet sizes mean its all standard, anyideas wy over fueling whats the accelerator arm and 5mm drill bit method to set it

All the jet sizes and the venturi you have quoted are of standard sizes

[Scoff]

forget what they have stamped on them, jets are often drilled and venturi's often machined out. you should definately check the size of the idle jet.

[jonnyshaw49]

how do u check them with a drill bit and a drill bit size chart or is there a specific way im new to all this thanks

[jonnyshaw49]

where can i get a set of standard jets?? if i have the head ported and polished should i be running standard jets . is there anyway of checking what psi my actuator is set at without taking it on the road i have a fairly big drive but not a road also how do i check the accelerator pump arm is set a 5mm with the drill bit method thanks