Technical Connecting 32/36 DFEV

[smahaley]

I’m in the process of resurrecting this 78 CS1 and opted for this Weber. Despite having the instructions that came with the unit and 2 diff shop manuals (and the internet) I haven’t found a simple diagram that says, yes, gas goes in here, this tube is for a return, this one for the charcoal canister, etc etc. I know I don’t have the spacer or anything there - I just dropped it on to have a look.

Any pointers are most welcome!

 

[bugsymike]

I can make a few suggestions, but I am sure others are more familiar with this carb.
The spigot nearest in photo of carb being fuel inlet, left a little and underneath looks to be a bolt with a gauze filter , re a return I am guessing if required it would go where the bolt on left opposite the inlet spigot, I can see a vacuum advance pipe bottom right of carb, the large pipe above the fuel inlet I am again guessing is to do with charcoal canister side, but to be honest they didn't have any of that stuff on the ones I worked on late 60s in UK.
The adjuster screw in from electric choke? I assume is the fast idle adjustment for when on choke.
Re the fuel inlet with carb off the car if you blow in what I think is the inlet then keep blowing and turn the carb upside down then float should rise to shut of fuel inlet as a basic test.
I am guessing with that sort of auto choke when go to start on a cold day, one press of accelerator pedal to allow choke flap to close.
On the round plastic body of the auto choke held on by three slightly overtightend screws, if you want the choke to come on earlier or later then slacken the three screws a little and revolve that plastic round bit a little, one way or the other, if you hold the throttle open a little then you can feel the tension on the choke flap increase or decrease to suit your climate, main thing is it closes enough to start and yet allow you to rev the engine a bit without stumbling and with air cleaner off as engine starts to warm up you want to see that flap gradually go to fully open so no restriction remembering that fast idle screw may need adjustment. I would use the factory settings to start with and then mark that position so if you alter it you still have the base setting if needed. Sometimes there is a graduated set of marks to guide you.
On the other side of carb we can't see you will have a normal throttle screw.
The idle mixture screw is just below the vacuum pipe for distributor advance.
Also make sure when accelerator connected that it goes to full throttle but most important it returns to full closed when you release the pedal.
I assume it is a progressive carb so on a light throttle only one flap opens then as you press further the second flap opens?
How many marks out of ten did I get?

 

[smahaley]

Thank you, @bugsymike, for your suggestions! I’ve marked up this version of the photo to be a bit more precise:
Red: there is a vertical sensor on the intake that I *think* could be plugged, as it just had tape on it when I got the car. Would like to know if that is correct..
Blue: I think this is fuel in from pump and after filter.
Green: this pipe has ridges on it to be really grippy. Given its position at top, perhaps it is the fuel in, and the lower (blue) smooth line is for overflow?
Yellow: there is a smaller diameter tube towards the base of the carb that could be a fitting to go to the charcoal canister? Or it could be a vacuum line as you pointed out, however my distributor is a simple mechanical advance and does not have a vacuum port on it.
Orange: hard to see but there is a blade connector for an elec choke. The original had a choke managed by water temp, I believe and has a solenoid with a blade connector. I wonder if I can use that wire that was for the solenoid on the new carb to connect the elec choke?

That’s what I’m noodling over and searching through the manuals etc … fun! Thanks for any further advice on the above - and I may just try blowing through the blue and green to see if there is clear evidence of “in” vs “ out”…

 

[bugsymike]

The red marked one I have seen before but don't know for sure, some kind of temperature controlled vacuum actuator? Is it my eyesight or has one plastic outlet been broken off it?
Blue I think is petrol inlet, you may try blowing and turning carb so float moves to check it as no fuel has gone through it yet. As an apprentice we used to doi that and taste petrol for hours after. Incidentally re filter most didn't have an extra filter, usually there was a coarse filter in the top of the mechanical petrol pump and another under the brass bolt I mentioned near the fuel inlet on carb (top right of red circle). Basically Carbs were more forgiving about small amounts of dirt that modern injection systems so didn't use fine filters. A reason some do as aftermarket fitment is for old rusty fuel tanks.
The green circle is I think a breather for top of float chamber, it may be connected to your charcoal filter system , but I am not sure, early carbs just vented to the atmosphere.
The yellow I think is vacuum but if no vacuum advance on distributor then may be connected to the black vertical unit in red circle. It's all guess work but I have seen vacuum controlled flaps on air cleaners for cold weather to bring heat from the exhaust manifold.
The orange circle electric choke wire will activate the bimetal spring thing inside to bring choke flap on or off, I am not sure where the power for that is controlled from.
I always preferred manual choke flap cable operated, so you knew what was happening. However the automatic ones we did have to adjust for correct operation, things like water controlled ones often cars had no thermostat or jammed open so engines ran cold and choke stayed on giving poor running/rich, etc.
The left side of the yellow circle is the accelerator pump with a diaphragm behind a four screw cover, they often split and leaked fuel. When working correctly and fuel in float chamber then looking down the air intake with engine off you should see a nice steady thin stream of fuel from a jet near top of carb aimed in towards the ventuarri. If dirty it would cause stumbling when you slammed your foot down on the accelerator when driving, it should give a progressive stream of fuel from start of actuating the throttle all the way to right down to full throttle, until pedal movement stops. It draqws fuel from the bottom of the float chamber and has a ball non return valve.
All this is from memory some fifty years ago, so @124BC1 will have more accurate details.

 

[smahaley]

The red marked one I have seen before but don't know for sure, some kind of temperature controlled vacuum actuator? Is it my eyesight or has one plastic outlet been broken off it?
Blue I think is petrol inlet, you may try blowing and turning carb so float moves to check it as no fuel has gone through it yet. As an apprentice we used to doi that and taste petrol for hours after. Incidentally re filter most didn't have an extra filter, usually there was a coarse filter in the top of the mechanical petrol pump and another under the brass bolt I mentioned near the fuel inlet on carb (top right of red circle). Basically Carbs were more forgiving about small amounts of dirt that modern injection systems so didn't use fine filters. A reason some do as aftermarket fitment is for old rusty fuel tanks.
The green circle is I think a breather for top of float chamber, it may be connected to your charcoal filter system , but I am not sure, early carbs just vented to the atmosphere.
The yellow I think is vacuum but if no vacuum advance on distributor then may be connected to the black vertical unit in red circle. It's all guess work but I have seen vacuum controlled flaps on air cleaners for cold weather to bring heat from the exhaust manifold.
The orange circle electric choke wire will activate the bimetal spring thing inside to bring choke flap on or off, I am not sure where the power for that is controlled from.
I always preferred manual choke flap cable operated, so you knew what was happening. However the automatic ones we did have to adjust for correct operation, things like water controlled ones often cars had no thermostat or jammed open so engines ran cold and choke stayed on giving poor running/rich, etc.
The left side of the yellow circle is the accelerator pump with a diaphragm behind a four screw cover, they often split and leaked fuel. When working correctly and fuel in float chamber then looking down the air intake with engine off you should see a nice steady thin stream of fuel from a jet near top of carb aimed in towards the ventuarri. If dirty it would cause stumbling when you slammed your foot down on the accelerator when driving, it should give a progressive stream of fuel from start of actuating the throttle all the way to right down to full throttle, until pedal movement stops. It draqws fuel from the bottom of the float chamber and has a ball non return valve.
All this is from memory some fifty years ago, so @124BC1 will have more accurate details.

Thank you, sir - yes that sensor in red had one of the two very small tubes broken off by some fool (mirror, please) and they were not connected to anything when I received the car.

I’ll keep looking around and thank you again for your guidance! Updates coming…

 

[s130]

There seem to be a number of DFEV variants.

As the carb is not bolted down yet try this. Turn the carb upside down and blow into the green pipe. If this is the fuel in then as the float valve will be closed then if there is no return bypass then you will be shut off. If there is a bypass then air will emerge out of another port, blue? Turn the carb right way up and the float valve will be open.

The red item is I believe like @bugsmike suggests is a temperature controlled vacuum port, possible used to choke & fast idle or emissions control. Certainly put a tube on this and suck or blow to see if it is open or closed at ambient temperature.

On DMTR carbs the large green is the fuel inlet and the smaller blue is the return. See attached file.

 

[smahaley]

There seem to be a number of DFEV variants.

As the carb is not bolted down yet try this. Turn the carb upside down and blow into the green pipe. If this is the fuel in then as the float valve will be closed then if there is no return bypass then you will be shut off. If there is a bypass then air will emerge out of another port, blue? Turn the carb right way up and the float valve will be open.

The red item is I believe like @bugsmike suggests is a temperature controlled vacuum port, possible used to choke & fast idle or emissions control. Certainly put a tube on this and suck or blow to see if it is open or closed at ambient temperature.

On DMTR carbs the large green is the fuel inlet and the smaller blue is the return. See attached file.

Thank you @s130 - very helpful and I will report back. Thanks for the diagram.

 

[s130]

I do have the old Weber Carburatori Tuning Manual, Publication 95.0000.54 which was reprinted in 1985 but no doubt was first written before 1985. A nice bible for how carbs and some of their more specific models work but no info on the 32/36 DFEV sadly because I suspect the EV variant post dates the publication.

Out of general info for other 124 owners then this manual has:

124, 1197cc, 32 DCOF, 2 barrels sidedraft (syncronised)
124 Sport, 1438cc, 34 DHS, 2 barrels downdraft (vacuum)
124 Special, 1438cc, 32 DHS, 2 barrels downdraft (vacuum)

Sadly not much help for you @smahaley

 

[Slotman]

Hi! Would have chimed in here but your 32/36 looks different than mine, I have both a real weber 32/36, and a Chinese knock off that's identical, and they both look like this, pretty much none of my pollution stuff is hooked up anymore, the blue is your line in from the pump...you may have a green wire for the electric choke.
Have you compared the overall height compared to your stock carb? As I mentioned previously, my carbs are shorter than the stock model, and required a spacer about an inch tall so the throttle linkage could work like before, and not bind...did you mention you purchased a "kit" that came with the spacer? Seems I've seen black plastic spacers before.

 

[smahaley]

Hi! Would have chimed in here but your 32/36 looks different than mine, I have both a real weber 32/36, and a Chinese knock off that's identical, and they both look like this, pretty much none of my pollution stuff is hooked up anymore, the blue is your line in from the pump...you may have a green wire for the electric choke.
Have you compared the overall height compared to your stock carb? As I mentioned previously, my carbs are shorter than the stock model, and required a spacer about an inch tall so the throttle linkage could work like before, and not bind...did you mention you purchased a "kit" that came with the spacer? Seems I've seen black plastic spacers before.

Hey @Slotman - yes, my Weber kit came with a spacer - I have not installed the linkage yet, so will do that after I confirm all the connections. Good news - I was able to confirm that fuel does pass from the tank to the front of the vehicle! (small victories and affirmations, I seek - yoda voice).

 

[smahaley]

Greetings good folk:
I have made some progress, during the small windows of time I have to tinker.

Here is a video which I hope will make you smile, or maybe cringe, or perhaps generate some pity.



Thanks, as always, for your guidance!

 

[smahaley]

Thank you @s130 - very helpful and I will report back. Thanks for the diagram.

In fact, that worked very well, thank you. Ports identified.

 

[smahaley]

Greetings good folk:
I have made some progress, during the small windows of time I have to tinker.

Here is a video which I hope will make you smile, or maybe cringe, or perhaps generate some pity.



Thanks, as always, for your guidance!

Yep - still some remaining questions...

 

[bugsymike]

Only just seen your video, the vacuum pipe at base of carb in the old days I would have said was for vacuum advance on the distributor, although I seem to recall you mentioned not applicable on your vehicle, I am not very familiar with charcoal filters, so if it is meant to be connected to that I would only be guessing?
What ever you do do not connect it to the fuel return. My thoughts as usual stand to be corrected, but I would say in the past I have seen fuel returns from the opposite side to the fuel inlet at this side of top of carb and I believe I mentioned that earlier in your post .
Can't see much of the oil breather circuit, I assume some form of flame trap by the engine block.
Re brake vacuum/servo fitting I assume there is a one way valve at the servo drum and the other end is connected to a similar size fitting at the inlet manifold.

 

[Slotman]

Don't know if this is helpfull or not....on my 79 , in order, 1st pic shows the large hose from air filter next to the electric choke goes to the flame trap/oil breather or what ever its called, next to the fuel pump, 2nd pic shows its attachment, 3rd pic shows where power brake hose attaches to the intake manifold, and 4th pic shows I plugged the 2 holes in between the valve covers...not using my egr...when I got my spider it was a California car in which the smog pump had been removed, hoses were just left willy nilly, some open vacume leaks that should have been plugged, and some hoses plugged that didn't need to.
Not in any way saying my hook ups are correct but I can state my car does run smoothly....hope this might be of help! Terry

 

[bugsymike]

Don't know if this is helpfull or not....on my 79 , in order, 1st pic shows the large hose from air filter next to the electric choke goes to the flame trap/oil breather or what ever its called, next to the fuel pump, 2nd pic shows its attachment, 3rd pic shows where power brake hose attaches to the intake manifold, and 4th pic shows I plugged the 2 holes in between the valve covers...not using my egr...when I got my spider it was a California car in which the smog pump had been removed, hoses were just left willy nilly, some open vacume leaks that should have been plugged, and some hoses plugged that didn't need to.
Not in any way saying my hook ups are correct but I can state my car does run smoothly....hope this might be of help! Terry

So on yours does the pipe at base of carb that I thought was a distributor vacuum advance actually go to the diahpragm on side of carb, I couldn't quite see.
Does yours have a fuel return and if so does it go where I though opposite the fuel inlet in same area, float chamber side?

 

[Slotman]

Hi bugsymike! The pipe at the base is running to my advance on the distributor, the carb I'm currently running only has a hook up for the fuel, I have experimented with both plugging the fuel return line, and leaving it open to let the tank vent? Currently it's open...

 

[bugsymike]

Hi bugsymike! The pipe at the base is running to my advance on the distributor, the carb I'm currently running only has a hook up for the fuel, I have experimented with both plugging the fuel return line, and leaving it open to let the tank vent? Currently it's open...

That is more inline with the sort of cars I worked on in the late 60s with vacuum advance.
On your last photo OPs new carb had a brass blank which is where i have seen return fuel line to the tank on some vehicles.

 

[smahaley]

Super helpful - thanks @bugsymike and @Slotman! Some progress today:
- ordered a long crankcase ventilation hose to communicate / connect up to the base of the breather on the new carb - which came with a 90 degree elbow that tightens onto that
- agree that my return line to the tank may remain a visual feature only Kinda shoulda not spent money and time on running new fuel return line to the tank! I've got a short run of rubber fuel line in the engine bay and I'll but a bolt / clamp on it to plug it.
- agree that the top of the charcoal canister should likely connect to the one available vacuum port at the base of the carb - thereby creating the vacuum that's helpful for the whole filtering process
- the barbed outlet at the very top of the carb will remain connected to the middle of the charcoal canister, with most info pointing to that as the logical connecting point for vapors escaping the top of the carb
- I've now added a fuel check valve between the fuel filter and inlet at the top of the carb.
- I tested fuel flow from the tank (using a fun process featuring a shop vac and steel straw) just to make sure my lines are all clear and good news we got juice to the front!

So! I'm just waiting on a couple of parts and then will connect the accelerator cable and move on to adding the radiator etc etc...

 

[bugsymike]

Super helpful - thanks @bugsymike and @Slotman! Some progress today:
- ordered a long crankcase ventilation hose to communicate / connect up to the base of the breather on the new carb - which came with a 90 degree elbow that tightens onto that
- agree that my return line to the tank may remain a visual feature only Kinda shoulda not spent money and time on running new fuel return line to the tank! I've got a short run of rubber fuel line in the engine bay and I'll but a bolt / clamp on it to plug it.
- agree that the top of the charcoal canister should likely connect to the one available vacuum port at the base of the carb - thereby creating the vacuum that's helpful for the whole filtering process
- the barbed outlet at the very top of the carb will remain connected to the middle of the charcoal canister, with most info pointing to that as the logical connecting point for vapors escaping the top of the carb
- I've now added a fuel check valve between the fuel filter and inlet at the top of the carb.
- I tested fuel flow from the tank (using a fun process featuring a shop vac and steel straw) just to make sure my lines are all clear and good news we got juice to the front!

So! I'm just waiting on a couple of parts and then will connect the accelerator cable and move on to adding the radiator etc etc...

I am still not sure about connecting that vacuum pipe to carbon filter, has anyone got any diagrams?
Re the return to the tank and blanking it off.
If Fuel tank isn't vented through a breather of a vented cap it can cause an issue. In the past when tank breather blocked either car will break down due to fuel starvation or I have actually seen a fuel tank collapse/implode until fuel cap removed. So you do need to know what your system is.
An advantage of a fuel return is it helps keep the fuel cooler if in warmer areas.
The crankcase ventilation pipe should have some form of flame trap, even if only a basic twisted wire gauze in the pipe.