Technical Seat Marbella Newbie - Carburettor Question

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Technical Seat Marbella Newbie - Carburettor Question

BellaTheMarbella

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Hi! I am new not just to owning a Seat Marbella, but project car in general. The idea was to get a little car I can learn things on and start my journey into DIY car fun. My first car was a Fiat Panda Fire and I LOVED it, but I didn't have the time or money to keep fixing it so had to give it up for a "sensible" car (according to my parents!) Since then I've always wanted it back...

This August I bought a little Seat Marbella as it's almost identical and super cute to boot.

I've done a service on her, named her Bella and have been generally coming up against various problems but nothing to keep her off the road at the moment.


I have just replaced the fuel hose as she was having difficulty starting. Ideally I'd like to do a clean up and service on her carburettor but I'm struggling to find the right kit to do so. In her service history documents there is a comment from a garage that there is a "homemade" gasket in the carb and I'm wondering if this is adding to her issues.


Any help on advice for what kit to use to service a 1993 Seat Marbella 903 Weber 32 ICEV 70 carburettor would be much appreciated.

I'm concerned that the previous owner had to resort to a homemade gasket!!!

Many thanks for any help 🙏
 

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Dragon Man

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hey here, Welcome!
you have the hybrid electro carb on yours. has an ECU but also a carb. its going back some years but i also had one.

for me the main issue i had was vacuum leaks. split vacuum pipes. as you look at the battery look in front of it kinda you should see a black flat round thing with 2 thick (fuel hose size ish) pipes going into it and a thin stiff vacuum pipe also going to it. check the thin pipe for chafing and also check all of the little rubber connectors.
on the carb there's also a disk shaped thing that is meant to control the choke.. use a bit of pipe and connect to this then suck on the pipe.. if you can keep sucking the diaphragm internally has failed. you can just blank the pipe off as a lazy fix the manually control the choke (more manually than usual)

an old school mechanic can attach a CO meter to the little pipe that sticks up in the engine bay from the exhaust manifold it should have a rubberish cap on it. using the CO meter they should be able to retune the carb to peak performance again. they can sometimes get it where the little AFC (auto fuel cutoff) solenoid can get a little stiff. its right there in the middle of the photo you took of the carb. take that out and give it a little wire brushing and a few forced actuations. can also bench test it to make sure its working. the little plunger on it should suck its self in when power is connected to it. not sure if yours is one wire or two.. if its just one wire connect it to the + of a battery and the metal body to the -. the plunger should retract. if not it may be faulty. if two wires just connect each wire up to a battery terminal. its not polarity conscious. if it works test to see if the ecu is sending power to the AFC solenoid first, but for a temporary fix if the solenoid is dead you can cut the end of the plunger off (with wire cutters its only soft brass) and refit it.. but only do this if you are sure its the solenoid that has failed.
running it like this for too long (months) will eventually poison the cat. the system is not 100% perfect as it does do it anyway it just burns it back off again when it gets hot. which is that funny bad eggs smell you get sometimes if you have been coasting up to a stop for a while using the engine to break.

wish i never sold the one i had. it was a really nice car.

try to get some rust proofing in the sills and up inside the wheel arches, also behind the trim in the rear quarters where the rear seat belt spools are :)
i recommend Dynax S-50 for its protection and ease of use!
 
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BellaTheMarbella

BellaTheMarbella

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Hi!
Thanks for your reply 😃 there is a lot for me to start looking into and I'm on rest days now so will take a look and get stuck in.
If the diaphragm is not working properly, I'm guessing would be impossible to replace? So just more manually control the choke is an ok option for a fix is what you are saying, yes? I'm wondering if this is the problem as when I first got her, she never really had this problem starting so I feel like something has happened along the way.

I will check all the bits you've mentioned and give an update!

She's a great little car, I'm learning loads as I go for sure. Thank you ever so much for your advice and knowledge!

Thanks again xx
 

Dragon Man

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yeah pretty much, when i say just more manual i mean that the flap wont automatically open its self when the engine is revved. if you leave the choke out for too long you will get a little red light flash up on the dash. i usually try to get the choke in as soon as i can though. these little engines do not take long to warm up. if you are interested, here is the marbella i had that i rescued from the scrap yard with only 19k miles on it!


wish my brother never sold it. i gave it to him as his first car.
 
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BellaTheMarbella

BellaTheMarbella

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Yeah I have noticed the engine light come on if I leave the choke out too long, it surprised me how quickly it warms up actually so I don't have the time to forget about it once I'm going 🤣

Wow, your scrap find was epic! I can't believe you let your brother sell it!!! I've had quite a lot to do on my Marbella since I've had her, and she's in nowhere near as good condition as yours was (with 75000 on the clock!) But she's so much fun to drive, I'm determined to bring her up to snuff and make a success of it.

I read through the thread and noted what someone said about the door panels hiding rust so I will check that out. Finding parts for them is pretty tricky. Also, as I see from your YouTube video, you took the dash off, my oil light doesn't come on when I turn the ignition on... I know she has oil because I check every time and already done an oil change not long ago but I was wondering, would that be the light in the dash not working or a sensor somewhere? I've been trying to research it but I am still stumped.


Sorry for picking your brains so much, I really appreciate it!
 

Dragon Man

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on the 903 engine the oil pressure sensor is on the back of the engine the opposite side of the exhaust to the oil filter. when you find it, it will have one wire going to it. all you do to see if it works is just touch that wire to the engine (or a ground with another wire) while the ignition is on. you dont need the engine running. this just earths the light in the dash to ground and makes the oil light illuminate. if the light illuminates i would change the oil pressure sensor. the oil pumps in these engine i know are good for well over 250,000 miles.

at 70k miles, it could probibly do with the valve tappets adjusting just to make them a little more quiet.
pretty much every part of the 903cc engine you have is compatible with the later 899cc engine found in the Cinquecento and Seicento SX variants so engine part are not so hard to find. with yours not having a distributor you do not have to worry about finding any replacements to that.

yes, theres a good saying with old Fiats like what we have.. Oil that goes into them, never leaves them. as when you do an oil change you just end up painting the insides of the doors and around the rear arches behind the fabric trim panels with it.
i prefer Dynax myself.

as for finding parts, most panda parts will fit. however suspension struts, dampeners, and wheel bearings is all from a mk1 panda, pretty much everything else is from a mk2 panda.
just ask on here if you are not sure!
 
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BellaTheMarbella

BellaTheMarbella

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I will get on that too!

Ah that's really useful to know about the parts. I've been lucky so far that she runs and been able to adapt bits and pieces but all the parts I've had to source are the Marbella specific ones 🤣🤣🤣 which has been fun.

Thanks so much once again for sharing your knowledge! 😁
 
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BellaTheMarbella

BellaTheMarbella

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Hi again!

So I've spent some time out in the cold checking on those things you talked about.

First thing was, I couldn't find the flat black round thing near the battery with any vacuum pipe anywhere!

Secondly, I was able to check the diaphragm and that seems to be working as I tested it as you said 👍

Thirdly, I went to check the AFC solenoid and I believe it's already been made redundant. I've attached photo of what I believe is the solenoid from your description, can you see that someone has cut the wires to it... I checked the service history and in the notes the last time it saw a mechanic (about 2000 miles ago) it was to deal with a non start issue. They say in the notes "Fuel Shut off solenoid inoperative, modified solenoid to prevent interference with ideal circuit"
What I think they just cut off wires to the solenoid, judging by the look of it.

So I'm kind of stumped now. Does this mean it will eventually poison the car like you said? If I get a new AFC solenoid, I'll need to find a way to power it. I feel like it's a can of worms!

In other news, you were quite right, I checked the oil pressure sensor and it needs replacing.

I've attached a picture of the AFC solenoid... What should I do now??

Many thanks again x
 

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Dragon Man

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those wires look like they have been cut. did you try to press the end of the solenoid in? it should push in and spring back. if it does that means that it is still trying to cut fuel off. as when it has power getting to it, it "opens" to allow fuel. those wires will be around somewhere, i recommend finding them then replacing the solenoid. if you can find a short bolt (looks like a standard 8 or 10mm would do it) with a copper washer or PTFE tape to seal the hole up for now, that would "temporary" fix it.

on your first post in the first picture, at the bottom there looks to be 2 red wires joined together by a blue crimp connector. that should not be joined together.. ive got a feeling thats a dead short.

heres something to try.. can you solder? try using a sharp blade stanly knife or something like that to shave away the plastic on the AFC solenoid. try to solder 2 wires onto it. it looks hard but i dont think it would be. when thats been done touch the 2 wires coming out of the solenoid onto the battery and see if the little plunger sucks its self in. if it does that means it does work and not at fault.

i know its a bit of a faf but you could then try connecting small 5w bulb or testing lamp to those 2 red wires and taking it for a drive. when you come off the throttle and coast that bulb should go out effectively indicating that it should be "cutting off" power to the solenoid stopping fuel getting to the engine.

as for poisoning the cat, that does take years and an older car usually gets away with it. before you take it for MOTs make sure to get the exhaust system really hot by keeping it in low gears at higher speeds.

you can "clean" the cat by revving the engine to around 2000rpm (yes i know, no rev counter.. just guess haha) and spraying a light misting of water in the air intake till you notice the engine start to bog down.. this effectively steam cleans the catalytic converter and really brings new life back into it. trick ive done with a few cars to bring the emissions right down again. you'll know its worked as you will get a lot of black (looks like very dirty oil but its not) water come out the exhaust. so maybe put something under the exhaust pipe to catch the drips as it will stain the drive.
we had to do this on our Marbella. as it was not running right when we go it.

if you can take a over head picture of your engine bay, i can highlight the thing i am on about. our marbellas was only a year apart so it cant be that different, take it with the air filter housing off as that really hides everything,

maybe i can spot something not right.

oh also it does pay to make sure everything on the carb "works smooth" fixed a few pandas where the carb flaps were seized up. good spray of wd-40 and work all the levers on the carb back and forth see if that helps.
 
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BellaTheMarbella

BellaTheMarbella

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You know it's been bugging me for a while what it was because in all the research I've done on the carburettor (such a newbie 🤦🏼‍♀️) never even shows the AFC solenoid in any diagrams so I was super confused firstly - wtf was it, then why tf has someone cut the power to it?!
It makes sense now, even if it has been tampered with.

Yes I can solder, so next lot of rest days I will have a look at doing that and having a test. I've been told that is need to go to Weber directly to replace the solenoid but we'll see how I get on with that...

Thanks for all the tips for the cat too. I have a good 7 months before the next MOT so I'm trying to get it in shape in good time before that, but who knows what the next can of worms will be... It's one thing after another 🤣🤣🤣

I will absolutely take pic of the whole engine bay, from watching your video (and I found couple more on YouTube) I think there is some variation which is fairly surprising as you say they are only a year apart. I have a feeling poor Bella has been abused over the years!

I'll come back to you with engine pic later in the week. 😁
 
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BellaTheMarbella

BellaTheMarbella

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Hi! I hope you are still happy to help, December ended up to be madness, sorry for the delay.

I hope you had a good Christmas and new year 😊

I have been trying to source a new solenoid but have been unsuccessful so far. I haven't had the chance to solder and it yet either. (Doesn't help I'm in process of selling house)

I have however come home from work today and taken some pictures of the engine bay for you, in the hope that you could shed light on where the bit you were telling me to check on (flat black round thing with vacuum pipe) might be?

Funnily enough, a previously unknown terrible repair to my exhaust failed the other day so that was a bit of a surprise. 2023 isn't going to be my year I can tell already.

Anyway, I'm managing to get her started on 2nd or 3rd attempt at the moment, but as soon as she starts she sounds very sluggish and I have to constantly rev the engine so she doesn't stall. The easiest and least annoying way of preventing her stalling is by just driving her immediately, but any junction in the first few miles is a bit dicey 🤣
It just sounds like not getting enough fuel, but I have no idea why 🤷🏼‍♀️


Many thanks once again 😊
 

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Dragon Man

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Well. this is an interesting case.

so it looks likes your Evap/Fuel vapour system has been removed!

the blue pipe with the yellow circle is what would go into that flat black round thing.

the blanked off pipe circled in blue is the vacuum that controls the flat black round thing.

the brownish pipe circled in red is the crank case breather that i am pretty sure should be vented into the air filter housing. its not a problem however as these engines are well known for building up mayo under the oil cap under normal use, it may have been an attempted fix to prevent this from happening.

the orange circled pipe is interesting.. that looks like a fuel line. it may be a blanked off part of the Evap system but it seems strange its blanked.

the bit circled green is more of something interesting i am pointing out. my marbella never had that, its a blanking plug for the older style engine that had the distributor. this is where it went into the engine to connect to the cam shaft.

that metal disc shaped thing next to the pipe circled in blue. that should have a vacuum line going to it.. check to see if the pipe is split.

if you are like me and you like incense sticks, light one up, run the engine and hold it around the carb. if you see any pipe outlets that start sucking in the smoke, blank them off. nothing should be sucking in a vacuum on the carb apart from the main opening.

i wish i was more help but i have forgotten a lot of things over the years... i just hope this has somehow been of some help

ff1.jpg
 
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BellaTheMarbella

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Ok... That sounds sort of essential. I really only have myself to blame buying a car to learn how it all works and getting completely mugged in the process 🤣

Thank you so much, that really is very helpful. Please may I have your brain?

Everything you have circled I have been wondering what they all were. It's been bugging me for a while, so thank you for that. I don't know what good my newly gained knowledge is other than knowing what it is I have lost 🤣

The blanked of bit of fuel hose you circled in orange is a new bit of hose because the previous blank was made in the same way and the rubber had perished so I did a like for like replacement. I also thought strange it would be randomly blanked. Much like everything else that randomly goes to nowhere.

I feel like I've gone way beyond my capabilities here but she runs I guess...

If she's missing the evap thingy, does that mean she'll fail her MOT? Or would they not look for that...

I shall whip out the incense and give your suggestion a go.

Many thanks once again for your time and help. Knowledge is power, yet ignorance is bliss 🤣
 

Dragon Man

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it wont fail the MOT for it missing. the actual carbon canister is in the front drivers side wheel arch. if you turn the steering all the way to the left and look up as if you are looking up to the headlight you may see it if you dont have wheel arch liners fitted.

i have some test for you to try out, they wont fix your tick over issue but its just interesting to know how these removed parts effect the car.

do you ever get a vacuum on the fuel filler cap by any chance when you undo it?

also with the air filter off, start the engine from cold with the choke fully out (closed like it is in the photo) then come around the front and rev the engine, the choke should automatically open as the engine demands more air due to being revved. if it does not its possible that little metal disc next to the blue circle may have perished.. not really a problem as it just makes the choke.. "more manual" however with what you have said it should be working fine.

like i said though you will never get a correct run while that solenoid has the wires broken off to it.
does it have any numbers on it or any kind of identification? i will try an look for one also.

as a bit of a bodge fix you could drive 2x very small screws into where the copper wires are then solder some wires onto them screws then wrap tape around it to stop the 2 wires from crossing and dead shorting.
i pretty much guarantee that this would fix your tick over issue.

with the cars age it may be worth taking it to an old school mechanic who has an exhaust gas tester. if you look at that photo, on the second to last red circle on the brown pipe theres that white bung. that bung goes down to the exhaust and its actually a testing point for an exhaust gas tester to sniff the exhaust gasses before the cat converter to tune the carb up nice. after all this time and people playing/blanking off things it could probibly do with a old school tune up.

as a bit of a side note this fault is a lot like you have a carb with a blocked idle jet. i get it on loads of old stuff that comes into the scrap yard i work at. usually on things that do not have a fuel filter. dirt gets into the carb blocks up the really fine holes the jet uses for measuring the correct amount of fuel and causes the engine to run lean or just blocks off fuel all together. it can be a real simple fix and say if its on an old lawn mower you can buy that for £10 or £15, just clean the carb and fuel system out then sell it for £100. this is what i did when i was in college :D
 

Iggy64

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Hi! I am new not just to owning a Seat Marbella, but project car in general. The idea was to get a little car I can learn things on and start my journey into DIY car fun. My first car was a Fiat Panda Fire and I LOVED it, but I didn't have the time or money to keep fixing it so had to give it up for a "sensible" car (according to my parents!) Since then I've always wanted it back...

This August I bought a little Seat Marbella as it's almost identical and super cute to boot.

I've done a service on her, named her Bella and have been generally coming up against various problems but nothing to keep her off the road at the moment.


I have just replaced the fuel hose as she was having difficulty starting. Ideally I'd like to do a clean up and service on her carburettor but I'm struggling to find the right kit to do so. In her service history documents there is a comment from a garage that there is a "homemade" gasket in the carb and I'm wondering if this is adding to her issues.


Any help on advice for what kit to use to service a 1993 Seat Marbella 903 Weber 32 ICEV 70 carburettor would be much appreciated.

I'm concerned that the previous owner had to resort to a homemade gasket!!!

Many thanks for any help 🙏
Hi there. Southern Carburettors
Hi! I am new not just to owning a Seat Marbella, but project car in general. The idea was to get a little car I can learn things on and start my journey into DIY car fun. My first car was a Fiat Panda Fire and I LOVED it, but I didn't have the time or money to keep fixing it so had to give it up for a "sensible" car (according to my parents!) Since then I've always wanted it back...

This August I bought a little Seat Marbella as it's almost identical and super cute to boot.

I've done a service on her, named her Bella and have been generally coming up against various problems but nothing to keep her off the road at the moment.


I have just replaced the fuel hose as she was having difficulty starting. Ideally I'd like to do a clean up and service on her carburettor but I'm struggling to find the right kit to do so. In her service history documents there is a comment from a garage that there is a "homemade" gasket in the carb and I'm wondering if this is adding to her issues.


Any help on advice for what kit to use to service a 1993 Seat Marbella 903 Weber 32 ICEV 70 carburettor would be much appreciated.

I'm concerned that the previous owner had to resort to a homemade gasket!!!

Many thanks for any help 🙏
Hi. Southern Carburettors in Crawley may have the service kit you are looking for.
 
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BellaTheMarbella

BellaTheMarbella

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it wont fail the MOT for it missing. the actual carbon canister is in the front drivers side wheel arch. if you turn the steering all the way to the left and look up as if you are looking up to the headlight you may see it if you dont have wheel arch liners fitted.

i have some test for you to try out, they wont fix your tick over issue but its just interesting to know how these removed parts effect the car.

do you ever get a vacuum on the fuel filler cap by any chance when you undo it?

also with the air filter off, start the engine from cold with the choke fully out (closed like it is in the photo) then come around the front and rev the engine, the choke should automatically open as the engine demands more air due to being revved. if it does not its possible that little metal disc next to the blue circle may have perished.. not really a problem as it just makes the choke.. "more manual" however with what you have said it should be working fine.

like i said though you will never get a correct run while that solenoid has the wires broken off to it.
does it have any numbers on it or any kind of identification? i will try an look for one also.

as a bit of a bodge fix you could drive 2x very small screws into where the copper wires are then solder some wires onto them screws then wrap tape around it to stop the 2 wires from crossing and dead shorting.
i pretty much guarantee that this would fix your tick over issue.

with the cars age it may be worth taking it to an old school mechanic who has an exhaust gas tester. if you look at that photo, on the second to last red circle on the brown pipe theres that white bung. that bung goes down to the exhaust and its actually a testing point for an exhaust gas tester to sniff the exhaust gasses before the cat converter to tune the carb up nice. after all this time and people playing/blanking off things it could probibly do with a old school tune up.

as a bit of a side note this fault is a lot like you have a carb with a blocked idle jet. i get it on loads of old stuff that comes into the scrap yard i work at. usually on things that do not have a fuel filter. dirt gets into the carb blocks up the really fine holes the jet uses for measuring the correct amount of fuel and causes the engine to run lean or just blocks off fuel all together. it can be a real simple fix and say if its on an old lawn mower you can buy that for £10 or £15, just clean the carb and fuel system out then sell it for £100. this is what i did when i was in college :D
Morning! Broken exhaust slightly distracted me from my original quest but I'm back on track now.

I haven't experienced any vacuum on the fuel filler cap actually. What would that mean if I did?

I will try giving the solenoid a bodge maybe later on today. Unfortunately the solenoid has no distinguishing marks or part number on it which is massively helpful. All it says is "Weber" and "V12 DC". I thought I'd found one but when I emailed the company to see if it would fit they said no which is a shame. If you do manage to find one on your travels that would be incredible. I've attached big pictures just in case you are successful!

I will definitely be taking her to an old school mechanic for a tune up though. She's clearly been messed about as you say so would probably be best for someone who actually knows what they are doing to take a look. I don't think I'll win any amateur mechanic prizes anytime soon!


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