Fuel Filter

[Alex'n'Ane]

I seem to be having problems with 'dirt' in the carburetor and was wondering whether or not minors had a fuel filter fitted as standard, and if so where about it is located? If not has anyone fitted one? and where?
Thanks.

[eastona]

don't think there is one as standard, although is there a gauze strainer in the fuel pump? (not sure as I have a non standard pump). I have an off the shelf in line filter in between the pump and carb which does trap stuff, but not that much and it gets changed every other service or so.

If you're have a lot of problems, maybe the tank is rusty? It may be better (although more expensive) to sort the cause.

Sometimes rubber fuel pipe can deteriorate inside?
Andrew

[bmcecosse]

SUs are normally very tolerant - and yes there is a gauze filter in the electric pump - so not much should get past it. Of course - ssomeone may have thrown it away in the past! Why do you think you have this problem ?

[mike.perry]

Undo the lid on the float chamber and look inside to see if there is any sediment in the bottom. Dirt is rarely a problem in normal use.

[rayofleamington]

the in-line filters are worth having as they keep the carb clean and are inexpasive and easy to install.
I've only ever had one get blocked and that was because I 'forgot' to change it on a car that was off the road since the early 70's. The fuel tank had a lot of 'varnish' (dried out fuel residue) so that probaly caused my problem.
Normally they have a clear body so you can see if they are still 'clean' - usually they are good for 20,000 miles or more but it depends if you get dirty fuel or dirt from the tank.

[bmcecosse]

But if you fit it after the pump - the pump filter will have already caught all the dirt! And if you fit it before the pump - then the pump has to struggle all the harder to pull fuel upwards from the tank (now through the filter) - and this can cause problems in hot weather - although possibly ok at the moment!

[eastona]

The pump filter's pretty coarse compared to an inline filter. The pump one's more of a fine tea strainer, getting the big chunks whereas the inline one is a bit like a coffee filter, getting fine powdery stuff.

They're right though Alex n Ane, these are usually fairly tolerant of dirt, hence the rudimentary filtration fitted as standard.

Is a lot getting through to the float chamber? Is it fine powder, rust or something else?

Andrew

[Alex'n'Ane]

Thankyou for the responses, and yes this did come about as there seemed to be a bit of 'dirt' in the bottom of the float chamber. I think the 1'st job then is to rebuild the spare fuel pump and check the gauze filter on that before fitting it. I may fit an inline filter also as a temporary measure, in order to see if the tank is indeed rusting and a new one needed.
Alex

[bmcecosse]

There's always a little bit of fine dirt in the base of the bowl - that's why it has a recess ! It doesn't normally cause any problems - SU doesn't have any 'fine' jets - so can cope well with dirt and water in the fuel. Just one of it's many clever and fine features! I wouldn't waste money on a filter!