I wonder if electric fuel pumps could be partly to blame It seems a lot of people who are having issues are all running them. Could it be that they put pressure on the carbs valves as soon as the ignition is switched on, where as with the mechanical pump its a bit slower and gentler.
A solenoid valve will cut off all fuel from the tank to the pump (and then to the carbs). If you switch it off on the move, your engine will stop
Yep, I get that. What I mean is if your needles do start to wear the solenoid will prevent fuel passing into your engine when parked up and that’s great. But you’ve still got worn needles - so you can only over fuel at idle and not over fuel at driving rpm?
With the shutoff solenoid and an AFR gauge , you notice that the engine is starting to burble at low throttle, and sort of miss fire gently, running rich before the flooding to a halt. So I dont ever get the engine filling up with petrol bit. I also have one of the nice CSP fuel pumps that puts out a reasonable 3.5psi and that also helps - the previous pump also worked but the pressure was quite a bit higher. Basically when I rolled up at Southern Garage Services back in 2011, Scott basically told me to fit a shutoff solenoid with a Weber carburettor. So I did.
Well…you don’t want worn needles You don’t want the float bowl leaking fuel down the throat of the carb under any circumstances.
Way out westie - he say 8mm is the biz. @Dubs Gotta be worth a try as 6mm did nowt good for me. 8mm would mean that the float is deeper in the Petrol bowl, so more pressure on the needle . May also ensure better closing and less vibrating about
It should mean the level of fuel is lower in the bowl – but if the needle valve leaks it’ll still overflow.
Does someone do Viton-tipped valves for ICTs? Can get them for Dellortos. Also: how thick are the top cover gaskets in your refurb kit?
The only place I’ve seen Viton tipped valves for Weber’s is aircooled.net. But I haven’t looked very hard. Rotary pump, no regulator, no cut-off valve, no Viton tipped needle valves, no problems.
So why has Way out Westie suggested that moving from 6mm to 8mm is the specific fix for stopping overfuelling and needle wear in Weber icts? not saying it’s sound, I’m just wondering what the rationale is?
Good question, the Bug has one of these, be interested if @77 Westy knows the answer. Meanwhile, I'll do some research.
I suppose I should know, but I don’t. What advantage would there be if it did? Apart from filling the tank for nothing.
I have no idea. If the float floats and the valve doesn’t leak all that lowering the level will do is, err, lower the level. But Way out Westie has a nice website so it must do something good. Did they also say you shouldn’t vent the fuel tank into the air-filer because it will explode, or was that on some other site?
It will have an effect on the mixture. Probably not noticeable but would weaken it in certain areas, lower fuel level at the emulsion jets weaker mixture in mid throttle/ rev range.
