Got back from Camperjam and noticed fuel dripping from the LH carb (1800cc type 4 engine). It seemed to be coming out from the throttle spindle. All fuel pipe connections were tight and dry. Has anyone seen this before? Is this likely to be a float or a float valve problem? I was worried about it catching fire. I'm guessing that while the engine is running, the excess fuel is drawn into the engine. But when switched off, it runs down inside the carb onto the closed throttle flap and then out through the throttle spindle and onto the exhaust. I've removed the carb but don't want to open it up without being sure where the problem is. If it is due to a leaky float or worn float valve, does anyone know where I can get new ones? JK and Heritage don't seem to do them for type 4 engines. Will a 2000cc float and float valve fit an 1800cc carb? Thanks for any help.
its leaking from the throttle spindle bearing .... its just worn will also suck in air and not run as well .... you can get these refurbed , i`ve only done single solex type bushes and not twins so don`t know if the are a split bush bearing or something else ...
Likely to be the float valve not sealing properly. The worn spindle hole just provides a means of escape - it's not the cause.
Dont PDSIs have a fuel cut off valve on the carb. Agree with what has been said above ie spindle will be worn but float valve not seating but fuel cut out valve should minimise that if it works. Someone may be along shortly to point out im wrong here so hang fire until you have some more responses to confirm. Incidentally 17/18 and 2 litre floats and needles should be the same.
I had this happen once - at the same time the pulley was broken and constant sparks were flying round the engine bay - I would say I was lucky. My carb was awful anyway so I replaced it
The cutoff valve just shuts off fuel to the idle circuit, not the whole carb. Worth taking the carb top off to see what's happening.
Thanks everyone. That confirms my suspicions. I assume that if the float valve had failed big time then the engine would keep flooding. I'll take the top off and have a look. Problem is getting a new valve. Air leaking through the bearing doesn't seem to have affected the engine though - managed to average 25 mpg over the last two long trips, cruising on motorways at 60mph. But the leak was probably there when the carbs were balanced last year!
It's likely crud or wear where the float operates the valve. You can usually reuse the valve (which may be the same as the ones in the 34 PICT 3 refurb kits). Blow through it and press the plunger to see if it seals. Wear in the spindles can upset the mixture (making it lean) if it's bad enough, as air gets sucked through under the throttle plate. Might be worth pulling a plug or two to see what colour they are. Apart from that - if it ain't broke, don't fix it !
Thanks Snotty, wise words. I'm already worried that I may have upset the balance just by removing the carb. Hopefully the linkage hasn't moved. Presumably it would be running lean only on the LH side. It might explain the good mpg. Is it white plugs means lean mixture?
My westy (1700) had worn carb spindles when I got it. It went really well on choke so I knew the engine was ok, but acceleration was hopeless and really struggled to get to 60mph. Sounds like yours is ok in this respect? Then my solex pict 31 single carb that dripped from the spindle when the float was set wrong isn't worn at all, put petrol will seep through anywhere there's the slightest gap. Based on that^ the petrol leak doesn't mean the carbs are worn, though of course they may well be.
