Alfa Romeo Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
53 Posts
Discussion Starter · #1 ·
Fitted an electric pump to the sud and engine starts and runs ok but needs carbs balancing etc. If i leave it to tick over, after about 30 seconds the o/s carbs seem to flood with petrol and the engine stops.
Take the plugs out on that side and find both wet with fuel and not firing.
Ive fitted a return line back to the tank overflow lug on the filler pipe and the fuel does flow back as i can see its movement. The metal filler pipe has two lugs on it and the line back to the carb is on the small one with the other blanked off. The other pipe which comes from the tank that should go to it is also blanked off too. Should these two be conmected?. Should the tank be vented at all?.
Of course i suppose the fault could be the carb for some reason. Any ideas?
 

·
Registered
Joined
·
2,788 Posts
Check your float valve in the carb. I had the same problem when I fitted an electric pump. The return to the tank should probably be connected although ive read that there are people using the twin carb setup without the return. Not sure if thats with mechanical or electrical fuel pump though so id reconnect it just in case.
 

·
Registered
Joined
·
2,673 Posts
Generally fuel tanks are only vented to let air in (one way valve) because otherwise your car would stink of petrol. Sounds like your float valve isn't sealing properly.
 

·
Registered
Joined
·
2,788 Posts
Ok will have a look in the carb. Does the tank need to be vented though?
Not sure to be honest. Someone drilled a small hole in my filler cap before I got the car and the Sud has one of those universal caps so doesn't seal properly anyway. Id start with the float valve, it solved my problem.
 

·
Registered
Joined
·
30,370 Posts
Before emissions regs got tighter, Petrol caps were vented.
Now they are completely sealed and Petrol vapor is stored in charcoal canisters with an ECU controlled valve to allow it into the inlet manifold.

But that probably isn't the cause of your flooding.
 
G

·
which pump have you used?

it shouldn't supply more than about 4psi fuel pressure.

would agree with above though, check the float valve to see if it's stuck. also check the float itself, they can split or get pinholes and fill with fuel..
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #8 ·
It was one that was recommended on here. Just a very simple thing really. It seemed to be ok for a week or so then this problem appeared. Had a similar problem about twenty years ago with a s3 so took it to westune who took a piece if wire out of a jet!.! Oh happy days"
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #9 ·
Ok i have cleaned all jets examined the floats etc and all seems fine. Starts ok and now will tick over without flooding but uneaven.
Took plugs out on that side and found them to be wet with petrol, not dripping but more damp . The other side are dry and brown ish.
The spark seems to be rythmical when attatching a strobe between the distributor and plug. The plugs do seem to be a little on the cool side bosch w5. would a hotter plug help?. Also the deloroto carbs only seem to have one mixture screw in them!. Building up courage to screw it in a bit, what do you think?
 

·
Registered
Joined
·
2,788 Posts
If you only have 1 mixture screw then something is wrong. You should have one at he base if each barrel of the carb. It'd certainly be fairly rough if you cand adjust the mix on one cylinder.
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #13 ·
Ok. Screwed in the one mixture screw in the offending carb half a turn and fitted some bosch wd 8s and its running better now. Perhaps i'm used to my 156 and my super smooth ford z tec, and have forgotten how a bit ' rough and ready' these flat fours are!.
 

·
Registered
Joined
·
2,788 Posts
What carbs have you got? I was assuming Dellortos but was mixing up my threads. If you are missing an adjustment screw, it could explain why its still running badly.
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #15 ·
Yes they are delorotos . Looks as if the tamper proof caps have never been removed!. And the two that have (one on each carb) are the only two that are available for adjustment.
Really do prefer a single twin choke carb, you know where you are with them and if i had one would swap them for a webber!
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #17 ·
I still think the sud lost something when they put the twins on it.
I have had 17 since 1980 and still think the 1350 ti was the best one ever produced.
Had two 1200 too and for some reason they just seemed right!.
 
1 - 17 of 17 Posts
Top