Good morning all,
Can anyone tell me where the idle jets are on a Weber 34 DMTR?
As I recall, when the air filter box is removed, a row of four vertical jet holders is visible between the two barrels. My guess is that the outer pair contain the idle jets, but can anyone confirm this before I do anything stupid? My car won't idle, but since I nearly ran out of fuel the other day I'm fairly sure that I just filled the float bowl with tank gunge and blocked up my idle jets. Having just driven through rush-hour traffic for the best part of an hour, I finally found a use for that manual accelerator lock thing...
Please help me have a more relaxed drive home tonight!
Cheers.
Andy
Help please! 34 DMTR
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keith turner
Re: Help please! 34 DMTR
Hi Andy
That must be an early car you have there haven't seen a 34DMTR for ages. The outer of the 4 brass "jets" are the slow running jets & the idle fuel setting is adjusted by the screw in the bottom flange the main jets & emulsion tubes are the middle two. Check that the choke flap is not closed -linkage disconnected or broken this can happen & engine will not slow run, chokes itself to death.
Best bet is to clean out all the jets & air passages with an airline, remove the top of the carb carefully try not to damage the gasket & check in the float bowl for muck. There is probably a mesh filter in the fuel inlet connection.
Idle adjustment is controlled by the fuel setting screw in the base flange & the bypass screw higher up the body in a tubular part of the casting that sticks out horizontally further than the other screws.
setting up the idle - (warm engine)
screw in the bypass right home adjust throttle opening screw & fuel setting screw until engine ticks over at 700 -750 rpm tighten locknut on throttle screw. then screw out the bypass screw until it ticks over at 800 -850 rpm.
Hope this helps I have a diagram of the carb or if you have an old Haynes Manual for the Lancia Beta there is info on these carbs. You can still get jets & repair kits from Weber Agents but the carbs are no longer available new.
That must be an early car you have there haven't seen a 34DMTR for ages. The outer of the 4 brass "jets" are the slow running jets & the idle fuel setting is adjusted by the screw in the bottom flange the main jets & emulsion tubes are the middle two. Check that the choke flap is not closed -linkage disconnected or broken this can happen & engine will not slow run, chokes itself to death.
Best bet is to clean out all the jets & air passages with an airline, remove the top of the carb carefully try not to damage the gasket & check in the float bowl for muck. There is probably a mesh filter in the fuel inlet connection.
Idle adjustment is controlled by the fuel setting screw in the base flange & the bypass screw higher up the body in a tubular part of the casting that sticks out horizontally further than the other screws.
setting up the idle - (warm engine)
screw in the bypass right home adjust throttle opening screw & fuel setting screw until engine ticks over at 700 -750 rpm tighten locknut on throttle screw. then screw out the bypass screw until it ticks over at 800 -850 rpm.
Hope this helps I have a diagram of the carb or if you have an old Haynes Manual for the Lancia Beta there is info on these carbs. You can still get jets & repair kits from Weber Agents but the carbs are no longer available new.
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Andy
Re: Help please! 34 DMTR
Thanks very much for all that info Keith.
(by the way, yes, it's an oldie: 1974).
On the day when this happened, I also had no radiator fan, so I had to sit in the usual morning traffic jam with the heater fan running flat-out, juggling between right foot and right hand to keep the revs up whilst praying that the heater would evacuate enough heat to get me to work without cooking the engine... (it did).
Determined to avoid a repeat of this, I pulled out the idle jets before the homeward journey and found that one was blocked up with grey powdery stuff, a bit like limescale from a kettle. Once I had blown this out, the car started and idled fine, so I haven't needed to adjust the carb settings.
Since you clearly know your way around these carbs, could tell me why there is an electrical connection at the back of the carb (single brown wire I think)? I'm just curious, because I can't think what it's there for, but is there such a thing as an "idle solenoid"? I once had a VW Polo which would stall instantly if you pulled this connection (I figured this out after the engine had died on me mysteriously several times, because the wire had fallen out...). Different carb, of course.
Thanks again.
Andy
(by the way, yes, it's an oldie: 1974).
On the day when this happened, I also had no radiator fan, so I had to sit in the usual morning traffic jam with the heater fan running flat-out, juggling between right foot and right hand to keep the revs up whilst praying that the heater would evacuate enough heat to get me to work without cooking the engine... (it did).
Determined to avoid a repeat of this, I pulled out the idle jets before the homeward journey and found that one was blocked up with grey powdery stuff, a bit like limescale from a kettle. Once I had blown this out, the car started and idled fine, so I haven't needed to adjust the carb settings.
Since you clearly know your way around these carbs, could tell me why there is an electrical connection at the back of the carb (single brown wire I think)? I'm just curious, because I can't think what it's there for, but is there such a thing as an "idle solenoid"? I once had a VW Polo which would stall instantly if you pulled this connection (I figured this out after the engine had died on me mysteriously several times, because the wire had fallen out...). Different carb, of course.
Thanks again.
Andy
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lancisti mikele
Re: Help please! 34 DMTR
hi andi
this connection is very important,stpps the
engine when its very hot, normally in italy. simply gas interuption
mikele
this connection is very important,stpps the
engine when its very hot, normally in italy. simply gas interuption
mikele
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Andy
Re: Help please! 34 DMTR
Thanks Mikele,
I didn't know the carb was that clever.
I guess it just resets itself as the engine cools?
Andy
I didn't know the carb was that clever.
I guess it just resets itself as the engine cools?
Andy
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keith turner
Re: Help please! 34 DMTR
As far as I remember it is just an electromagnetic cut off valve to stop the engine running on when you switch off the ignition. I had forgotton it, if it is broken or disconnected the engine will not slow run. Usual test switch on the ignition, pull off & replace the connector the solenoid should click, it usually has a short length of wire with an inline connector. If it is broken & I'm not sure if you can get a spare as a temporary measure unscrew the unit - petrol will leak out - & cut off the end (moving part) this will allow petrol to flow to the slow running jet but the engine may run on when you switch it off - make sure it is broken check it across a battery before you butcher it! it may be the wiring or a fuse broken.