Fuel filters

[mickthefitter]

Does anyone run a twin carb Marina or an MGB with an in-line fuel filter under the bonnet? I fitted one as a precaution against any sediment in the tank reaching the float chambers and blocking the jets, but I'm getting the impression that the carbs are drawing more fuel than is entering the filter, and my mate Dennis pointed out that any air in the filter compresses. This Marina has previously had a fuel filter that had been removed when I got it, but it also had a leaking fuel pump, weeping float chamber gaskets, etc. which were all alternative sources of problems. Dennis has given me a couple of small mesh filters for motorcycles and suggested I fit one before each carburettor, instead of the plastic 'can' coming off the pump, but I just wondered if anyone else had experiences with using fuel filters.

[morris_carl]

The carbs use the fuel from the floats ,not from the filter,so can't see why there would be any problem ,filter pre pump,then the fuel from the pump is pure fuel filling the floats,no problem

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[mickthefitter]

That could be the problem then. Filter is fitted after the pump. I didn't realise there was a right way or wrong way. I had a Cortina with a previously installed post-pump filter, and I did the same on my Hornet, which had the electric pump on the subframe at the back. That was plagued with float chamber issues before I put a filter in. I'll take a look and reconsider the location. Cheers.

[david painter]

I use MAHLE KL13 inline filter on the pressure side if the pump about 6 inches before the carbs on my MGB. Never had any problems
Dave

[1972TCCOUPE]

I only used the cheap and cheerful plastic filters fitted after the pump on both my tc's. Even with the electric pump the filter is never full. Both run okay.

[morris_carl]

Can be before or after,I just always prefer before as they are only rubbish plastic,if it goes pre pump its not gonna cover everything in fuel and go up !

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[1972TCCOUPE]

Good point,I may move mine.

[Morris McKinnon]

I put a filter before the pump. The pump has a built in filter but they're not very good. Having the filter before the pump stops the crappy pump filter getting clogged. I've a very dirty tank so need to change my filter every couple of months otherwise the car starts jerking when calling for more fuel on hills and such.

[mickthefitter]

Well, I suppose if I try a new location before the pump it would only be to see if the plastic filter fills up better before the car goes in for tuning next week. I'm not planning on driving it apart from maybe put some more petrol in it as it is quite low - though I put a fresh gallon of the best stuff in from a petrol can before I fired it up for the first time. And yes I know petrol ages, but whatever was left from last year did have supposed stabilisers and ethanol protectors added. I think the mechanical pump mounted on the block is further away from the carbs than the six inches Dave mentioned in his MG. I assume the model number of filter mentioned must be the sort I've seen listed on the Mini Sport site for high performance Minis. I just thought it was strange the engine faded away and stopped when I put my foot down, and took 3 or 4 cranks to restart.

[david painter]

Doesn't have to be 6 inches, it was just convenient to put it there. I use MAHLE filters exclusively at work and have a box full of KL13 I use them in my gas bench. Your complaint sounds fuel starvation if you have the cotton covered black fuel hose on the suction side, this perishes internally and sucks in air instead of fuel without showing any leak.
Dave

[mickthefitter]

While the car has been off the road Dave I've renewed every piece of flexible fuel hose with new ethanol proof black hose, not the braid covered stuff admittedly but it is absolutely new modern stuff. I think the only section that was original anyway was the short bit from the tank near the differential, which while quite hard, seemed to be in better condition internally than the later 'old' stuff running under the floor that was held on with nasty little jubilee clips rather than proper fuel pipe clips.

[Morris McKinnon]

My filter too always looks empty but the car runs fine. I did find that a loose pipe caused my car not to run at all. It was the piece your talking about at the fuel sender end. The clips had rotted away and air was being sucked in from that area. Fitted new clips and has been fine since.

[JubileeNut]

Kevin knows all about that bit of rubber hose

[fruity]

Kevin knows all about that bit of rubber hose

Paul you just sent shivers down my spine!


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[PHUQ]

I have heard of people having fuel evaporation issues due to those filters if they are mounted in a hot place- I know yours hasn't just been suffering when hot so it's not your issue but something worth thinking about in general. The Dolomite used to suffer from evaporation until we moved the filter but we did a load of other work at the same time so it might not be related.