aw Cummon folks - I cant believe that no-one on this forum can tell me where the vacuum pipes go from the carburettor on a 2.5 petrol engine.

Ok - i know one goes to the distributor vacuum advance mechanism and another goes to a "T" piece in the pipe that runs between the oil filler cap and the carb air inlet pipe. But where does the third one go?

and no - i dont mean the fuel pipe ;)
 
It may go nowhere!

Many carbs need to have a breather pipe from the float chamber to the outside so the fuel can level out properly and not surge due to pressure changes when your right clog goes on and off the GO pedal. I suggest you fit a bit of pipe and lead it UP a bit somewhere tidy. Make sure it doesn't get blocked.

The little pipe is fitted JUST downstream of the butterfly valve and ADVANCES the ignition timing when the engine is running on light throttle because the mostly closed throttle causes a good bit of vacuum, but when you clog the gas the throttle opens up, kills the vacuum, and the ignition retards thus avoiding you blasting in the tops of your pistons by detonation.

The biggie pipe is probably for your brakes servo.
 
more info required please folks.

it appears there are two type of Webber carbs fitted to 2.5 petrols.......

one has one solenoid next to the fuel input - for use with mechanical fuel pumps.
the other has two solenoids (an additional one on the side of the carb) for use with electric fuel pumps.

It seems I have the latter fitted to an engine with mechanical fuel pump, so the second solenoid (the one that works) is not necessary and is something to do with the "starting circuit"!!!!!!:eek: The solenoid which should work, but dont work (wire snapped orf) is a vent valve solenoid!
The carb is also supposed to dump unused fuel back to the fuel tank - but there aint no return pipe that I can see.

oodles of Questions....
duz anyone have a spare solenoid wiv the wire attached?
has anyone successfully repaired one of these solenoids (I am havin a go)?
are there any other diffs between Webber carbs fur elec and mech fuel pumps?
how is the excess fuel returned to the tank?

any ideas folks - piccies wud be nice too (coz I can understand them)


ps local stealer wants £28 fur a solenoid "if they arent obsolete"!:rolleyes:
 
try a scrappy fer yer solinoid cos am pretty sure the renault fuego uses the same one so it might be a common part used in lots of carbatooters.

are you sure one of yer 'vaccuummm'? pipes int the return. and if yer got a mech pump yer dunt need a return so why bover.
 
yu may well be rite, Slob - unfortunately I dont know which pipe mite be the return - maybe its just pumping surplus fuel ont the floor (or exhaust?)
 
well use yer hand cranker on the pump and watch where it comes outta, if any does come out
 
Reet - against current finking - "Expert auto sparky" and stealers - I reckon the solenoid can be fixed. So I is havin a go and replacing the crap auto wire with silicone hi-flex so it shud last longer.

if requested - piccies mite follow;)
 
Yup - it can be fixed -

piccies are......
1) problem - wire breaking at or very near solenoid.
2) view on top of solenoid with fibre/copper washer and broken wire.
3) exploded view of components once top has been tapped open.(l-r - washer/case/rubber washer/bobbin/insulator/top plate/wire.
4) removing insulation tape from around top section of bobbin, ensuring coil wire is not broken.
5) unwinding old wire partially around bobbin (be very careful of bobbin wire which goes over main wire about half way around).
 

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Thanks to Adz for pointing me in this direction - I post for others ................

On a webber 32/34 DMTL. The solenoid facing the front of the truck vents the float chamber when the ignition is off ,when you turn the ignition on the solenoid plugs the vent,that`s all so the engine will run fine even if the solenoid is faulty. The solenoid on the passenger side of the carb is the idle cut off valve,its purpose is to prevent `run on ` so when the ignition is switched off the solenoid plunger blocks the fuel channel in the idle circuit...to check it ...with your engine warm and ticking over remove the supply to the solenoid and your engine should stop UNLESS it is so badly set up that the throttle stop has been wound round to provide a tick over......
 

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