Traction running rich

C

CARPETSNAKE

Member
Tadpole
Joined
Feb 13, 2012
Messages
33
Location
vermont sth, melbourne
Hi Everyone,
Have a problem with my L15. Starts and runs beautifully but after about 10 minutes starts to run rough. Pull out the plugs and they are all sooted up. Exhaust is also black. Clean the plugs, put them back, starts well and runs for a few mins then same thing happens. I've cleaned all carby jets, increased the thickness of the washer under the float valve, adjusted the mixture screw, all to no avail. It has a 123 ignition fitted. Got me bamboozled! Help! Thanks, Rod Smith
 
Presumeably the choke butterfly is opening fully when it is asked to (by pushing the knob in)?
 
Rather than putting washers under the float valve, try a gentle bend of the tab that pushes on the needle.
Thre air cleaner is not infested by rodents is it?
Try it with the air inlet tube off the carby.
 
How well is the needle valve fuel shut off sealing ? You could take the top off the carb and hand pump the fuel pump to see if this is a problem.
 
I think there is fuel leaking into the carby through imperfections in the washers under the float valve.

Cheers, Ken
 
Buttercup said:
Presumeably the choke butterfly is opening fully when it is asked to (by pushing the knob in)?
Click to expand...
Bob, If the car has the original carb there is no choke butterfly. The Solex carbs on tractions have a Bi-Starter auxilliary carb operated by cable. It has 3 positions, closed -- normal idle, first stage -- slightly rich and open -- full rich. . It is possible to assemble the Bi-Starter with the disc 180 degrees out of position. This causes all sorts of problems but is easily rectified.
 
Many thanks everyone for your replies. Yes, it is a 32 PBIC carby and the choke is closing properly when the knob is pushed right in. I'm not sure if it has the bi-starter as mentioned by Gerry. I'll have to check that. If it does and the disc is 180 degrees out, then could this be making it run very rich, perhaps? The engine has been fully recoed last year but it hasn't been on the road. Someone mentioned to me that I need to get it out for a good run, get it under load to bed things in. Could this be the problem, perhaps. Or maybe hotter plugs?
 
Hi Rod , Dave G here , look forward to seeing your car as it will be no doubt looking superb by now! Your carby definitely has the Bi starter assembly so maybe check that out. Other issues apart from float level /pinholes etc . Are the jets correct size? has the needle and seat got obvious wear?
You could alway try another type of carby ( have seen that done )
 
pull the air cleaner off and look down its throat .... can you see fuel flooding into it from anywhere ?
 
CARPETSNAKE said:
Many thanks everyone for your replies. Yes, it is a 32 PBIC carby and the choke is closing properly when the knob is pushed right in. I'm not sure if it has the bi-starter as mentioned by Gerry. I'll have to check that. If it does and the disc is 180 degrees out, then could this be making it run very rich, perhaps? The engine has been fully recoed last year but it hasn't been on the road. Someone mentioned to me that I need to get it out for a good run, get it under load to bed things in. Could this be the problem, perhaps. Or maybe hotter plugs?
Click to expand...
The lever that the choke cable attaches to operates the Bi-Starter. If you remove the screws holding that housing you will see the disc to which I refer and you will get an appreciation of its operation. If this is not the problem then check that no fuel leaks from the bottom of the spray tower which is visible in the centre of the choke tube. If there are leaks at this point it will drain the float chamber and cause flooding. BE VERY CAREFUL if you decide to remove the spray tower! They can break very easily. The tower fits into the casting carrying the fuel supply at its base with a brass tube. This tube becomes loose with age, hence the leak. Do not twist with a screw driver using the air correction jet at the top of the spray tower. Just wiggle it very gently until it lifts straight up. To re seal the base reinsert with some thread locking compound such as 'Loctite'.
If in doubt leave it alone and take it to a recognised carby specialist.
 
thanks everyone, will try all those things and report back soon. The carby was checked over by a carby specialist but that was 5 or 6 years ago and it's been on the shelf until last year. Thanks for all your help.
Rod
 
Solex carburettors - flooding or excess fuel:
1. Cold start fuel system not right (Gerry)
2. Needle valve not seating properly (dirt/broken up banjo screen & rust)
3. ** Very pressure sensitive (about 2-3# is enough)
4. Float level too high (top upside down, gap is approx parallel with the float, when needle is closed)
5. Float leaking & holding fuel (too heavy to raise & close the needle valve).
 
Hi Everyone,
Checked operation of bi-starter (Gerry) and it seems ok - hole in disc lines up with hole in carby when 'choke" knob pulled out and hole rotates to face blanked off section in carby when knob pushed right in. Spoke to carby specialist in QLD this morning and he said if there is no indication of external flooding of carbs then float is ok. (Also checked fuel cut off with needle valve closed - again ok). He suggested the problem sounds like the main jet is too big. Mine is marked 13.5. Can anyone verify if this is the correct one. The carbs guy's website has about 8 different sized main jets (107,120,140,etc.) Apart from buying a few and trying them out, does anyone have any suggestions. Thanks in advance,
Rod
 
I think these are the correct sizes for 32PBIC:

26 Choke (Diffuser)
135 Main
190 Compensation Emulsion
50 Slow Running Idling
150 Idling Air Jet
125 Choked (Starting)
4 Choked Air Jet
11 Float weight
1.5 Needle Valve
50 Pump Jet
 
CARPETSNAKE said:
Thanks a lot, Catapole
I'll check all those.
Rod. (Sorry about the "catapult " Spellchecker)
Click to expand...
Hi :)
It was not unknown to find that people drilled out the main jet(and others) to cure some perceived problem. So you can check the size by using a number drill set if necessary(the shank end). A 135 = 1.35mm.
You can reduce the effective jet size with some fuse wire strands or two for a trial to see if that helps correct running. A short piece twisted in a circle each side of the jet to locate it.
Jaahn
 
jaahn said:
Hi :)
It was not unknown to find that people drilled out the main jet(and others) to cure some perceived problem. So you can check the size by using a number drill set if necessary(the shank end). A 135 = 1.35mm.
You can reduce the effective jet size with some fuse wire strands or two for a trial to see if that helps correct running. A short piece twisted in a circle each side of the jet to locate it.
Jaahn
Click to expand...
thanks jaahn, another useful tip.
Rod
 
CARPETSNAKE said:
Hi Everyone,
Checked operation of bi-starter (Gerry) and it seems ok - hole in disc lines up with hole in carby when 'choke" knob pulled out and hole rotates to face blanked off section in carby when knob pushed right in. Spoke to carby specialist in QLD this morning and he said if there is no indication of external flooding of carbs then float is ok. (Also checked fuel cut off with needle valve closed - again ok). He suggested the problem sounds like the main jet is too big. Mine is marked 13.5. Can anyone verify if this is the correct one. The carbs guy's website has about 8 different sized main jets (107,120,140,etc.) Apart from buying a few and trying them out, does anyone have any suggestions. Thanks in advance,
Rod
Click to expand...
To check the needle valve cut off hand prime the fuel pump until it cuts out. If it does not then look at the drain tube from the manifold. If fuel runs freely here then the float chamber is flooding. BTW when the float guides in the float chamber become extremely worn the float can stick and fail to close the needle valve. I suffered this problem once but it would only occur intermittently.
 
You must log in or register to reply here.
Top