5 replies to this topic

[HarveyT]

I have been having some problems with my float chamber recently, i.e. overflowing and just cutting out and spluttering.

 

I want to give the float chamber a good clean out as well as cleaning the whole carb but was wondering what is the best way to do this?

 

thanks!

[Wise Old Elf]

Alloy wheel cleaner works well to clean the outside of the carb and the bits inside. 

I went over mine with a carb cleaner after to make sure all the bits were clean.

[rally515]

Take it off, get a tooth brush and some thinners and scrub away :) , there are carb cleaning products like a spray version (which is Brill!!!  ) I cleaned an 850 engine block outside casing and it came up in its factory colours with no bother or damage, just removed whats not supposed to be there

[jaydee]

Use acetone, dont waste money on those new generation cleaners

[dklawson]

Cleaning is fine.  However, cleaning is not going to address the problem you are experiencing with flooding and spluttering.

 

You did not say which carb this is.  If an SU, it could be an HIF type with the float bowl integrated and located under the main carb body.  It could also be an HS type where the float bowl is to the side of the carb body and connected to the jet by a flexible tube.

 

On the HS carbs, the float bowl lid is secured by 3 screws.  Disconnect the fuel hose then remove the 3 screws to remove the bowl lid complete with the float and float valve.  Your fuel float could have developed a leak and may be partially full of fuel.  Repair is by replacement.  If it is not the float it could be the float valve.  Repair is by replacement.   When either the float or float valve is replaced, you just adjust the float level (see your service manual or the Burlen web site for details).  Early floats had metal arms and these were "bent" slightly to set the float level.  Later floats are all plastic and setting the float level is not typically discussed in the manuals.  What is required with the all plastic floats is to change the number (and therefore thickness) of fiber washers between the float valve and the bowl lid until the float height is correct.

 

If this is an HIF valve... I defer to others for specific advice.  All I can offer is that HIF carbs are best serviced by removing the entire carb from the engine bay for easier access as the bowl lid screws are almost inaccessible when the carb is mounted.  The HIF float is different than that of the HS carb but may suffer the same problem with leaks and the float valve.  I believe the only way to set the float height is by adjusting the fiber washers as mentioned above.  Again... others will have to clarify that as I don't work on HIF carbs.

 

Lastly, if you have the factory type fuel pump you should be OK.  If however, you have an aftermarket electric fuel pump, make sure it is not delivering too much fuel pressure.  SUs want about 2-3 PSI.  Many electric pumps exceed this and that will overpower the SU float valve causing flooding.  You can use a higher pressure pump with SUs but only when a fuel pressure regulator is installed between the pump and carbs.  The regulator is adjusted to drop the fuel to the 2-3 PSI range mentioned earlier.

 

By all means, clean the carbs to prevent debris from getting inside during your work but don't count on cleaning the float bowl to fix a flooding problem.  That said, there is a slim chance that IF your car does NOT have a fuel filter before the carburetor that debris may have gotten into the carb and the debris is stuck in the float valve causing it to remain partially open when it is supposed to be closed.  You won't know that or find it however without removing the float valve and cleaning it will best be carried out with spray carburetor cleaner.  Regardless, once this is sorted do install an inline filter between the pump and carb if your car does not have one.

[carbon]

As DK Lawson says, if you have not already got an in-line filter just before the carb then would get one installed. The plastic versions are only a couple of quid and do the job - stops the grot getting stuck under the needle valve in the float chamber.

 

After a couple of months you will be amazed how much grot the filter can catch...