Alfa Romeo Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
Hello, We have a 1973Veloce. The carburator was replaced about 11/2 years ago by a mechanic who is supposed to be expert in vintage Alfa. Suddenly, the car didn't start. I hauled the car to my mechanic and found that a part melted inside the carburator and there is serious damaged caused. It is better to change for a fuel injection system or find and replace the carburator? Thanks in advance for your suggestions. I am not certain of how to start the repairs.
1616897
1616899
1616898
 

·
Registered
Joined
·
8 Posts
Discussion Starter #2
Hello, We have a 1973Veloce. The carburator was replaced about 11/2 years ago by a mechanic who is supposed to be expert in vintage Alfa. Suddenly, the car didn't start. I hauled the car to my mechanic and found that a part melted inside the carburator and there is serious damaged caused. It is better to change for a fuel injection system or find and replace the carburator? Thanks in advance for your suggestions. I am not certain of how to start the repairs. View attachment 1616897 View attachment 1616899 View attachment 1616898
 

·
Premium Member
Joined
·
216 Posts
Im gathering it spit flames from the carb throat into the air box?
Fixing the damage and figuring out why there was a fire would be my priority, this isnt an everyday fear for our carb'd cars.
 

·
Administrator
Joined
·
12,590 Posts
Yeah agree with aaronsspider, this is an unusual occurrence and the cause needs to be resolved, fixed and then put on many happy miles.

Not trying to scare you, but I will be installing a fire extinguisher when I've finished restoring my car, just to be sure.
Pete
 

·
Administrator
Joined
·
12,590 Posts
That carburetor will need it's venturi replaced and the source of the problem resolved.

Never heard of this happening before ... ???

Check that you do not having a spark plug not firing issue as potential cause is too much fuel that was not igniting until suddenly it got a spark and boom ... you said you had a starting issue, so possibly the cause.

What is your starting procedure? Do you use choke (I don't, just a couple of pumps on accelerator)
Pete
 

·
Super Moderator
Joined
·
11,587 Posts
There was a discussion about air cleaner fires on the BB some time ago. I HAVE seen this before.
It IS a spit back igniting fumes collected in the air cleaner filter.
A clean up of that Weber, Stromberg 97 or whatever*, along with a GOOD tune up, with valve adjustment, ignition and timing check will go a long way toward preventing a recurrence.
*It makes NO difference who manufactured the "carb", it needs to be examined and cleaned up.
 

·
Push hard and live
Joined
·
9,657 Posts
Just curious....

You’ve started this thread in the 116 Alfetta/GTV6 area. That seems unlikely for a 1973 model year.

You might get more model-specific guidance in the correct model area and/or carburetor forum.
 

·
Super Moderator
Joined
·
10,637 Posts
Actually, Buckaroo1! started TWO threads in the Alfetta/GTV6 area, which I merged into one. That's why posts #1 and 2 above basically say the same thing. But I'm afraid I missed noticing that he has a spider!

Thread has been moved to the 105/115 spider section.
 

·
Premium Member
Joined
·
21,715 Posts
Could be really wrong timing (advanced) that caused a kick-back/snort. Sometimes the carbs "sneeze", which can open up the cold start valve, admitting more gas and air too. Check the basics, timing, compression, condition of ignition, condition of carbs.
Andrew
 

·
Registered
Joined
·
8 Posts
Discussion Starter #11
Im gathering it spit flames from the carb throat into the air box?
Fixing the damage and figuring out why there was a fire would be my priority, this isnt an everyday fear for our carb'd cars.
Thanks. DO you think we can leave the melted venturi inside the carburetor?
 

·
Registered
Joined
·
8 Posts
Discussion Starter #12
That carburetor will need it's venturi replaced and the source of the problem resolved.

Never heard of this happening before ... ???

Check that you do not having a spark plug not firing issue as potential cause is too much fuel that was not igniting until suddenly it got a spark and boom ... you said you had a starting issue, so possibly the cause.

What is your starting procedure? Do you use choke (I don't, just a couple of pumps on accelerator)
Pete
Hi Pete, Thank you for your answer. I do use the choke...
 

·
Registered
Joined
·
8 Posts
Discussion Starter #13
uld be really wrong timing (advanced) that caused a kick-back/snort. Sometimes the carbs "sneeze", which can open up the cold start valve, admitting more gas and air too. Check the basics, timing, compression, condition of ignition, condition of carbs.
Andrew
Thank you Andrew. Lots to check before driving our dear old "Fellini"again. (We named the car Fellini since it has a bit of an attitude, but it might be that when we got it, it came with some old issues and we didn't fixed at the moment.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #14
Actually, Buckaroo1! started TWO threads in the Alfetta/GTV6 area, which I merged into one. That's why posts #1 and 2 above basically say the same thing. But I'm afraid I missed noticing that he has a spider!

Thread has been moved to the 105/115 spider section.
Thanks. I tried to erase one and could not figure out how to do so.
 

·
Super Moderator
Joined
·
10,637 Posts
Thanks. DO you think we can leave the melted venturi inside the carburetor?
Simple answer is "no". It's tough to judge its condition from looking at your photo - the image in the dentist mirror isn't very clear. But if it's melted, then no, it won't work. Plus, there might be other damaged components inside the carburetor, so removing the carb and at least inspecting it (as well as changing the venturi) is what I would recommend. Note that venturis come in different sizes, so make sure the replacement you get matches the size of the others.

Thanks. I tried to erase one and could not figure out how to do so.
Easiest way to handle that situation is to report your own post. Click on the three vertical dots to the upper right of the post. Select "Report". Write that you'd like the thread moved, deleted, title changed, etc. Your friendly moderators will be happy to help.
 

·
Richard Jemison
Joined
·
7,394 Posts
Replacing the Auxillary Venturi (not the choke tube/Venturi) is easy. It is held in place by a little spring, and just slides out. These can be found through Alfa Part`s Exchange, or post a wanted thread here. The AV for a 40 DCOE should be marked 3.5. If your floats are brass, check for fuel in them as thty develop leaks.
.
BUT the cause of the fire is likely a combination of things. Starting with the most likely:
Fuel level too high in the carb(s) This will be ignited either by spitting(backfiring through the carb(s) or fuel leaking on the distributor/wires. There`s many threads on the BB about setting float level correctly.
But first with the cover & filter out of the way turn on the fuel pump. If you see fuel leaking out of either carb fuel level is too high due to incorrect float level setting,or the needle/seat isn`t shutting off fuel like it should be.

Cause of spitting is generally cam timing too advanced on the intake side (and possibly the exhaust cam) causing increased overlap. If these are the same cams that were in it with Spica FI, the mark on the front cam cap is at 114 LC. That is too retarded for the carbs, and an appropriate LC for that cam is 104 LC. Download a timing template from Centerlinealfa.com and re-mark the cap, and set the cam timing to that point.

Keep the carbs! This is minor....
 

·
Registered
Joined
·
6,829 Posts
Stange that the "experts" have not figured out that the OP does not have weber carbs....and they give advice on repairing DCOEs.
 

·
Premium Member
Joined
·
216 Posts
Are those Dell'Orto's?

If it were me I would take the affected carb off the car and take a good look at the insides and other parts with a flash flight, take some pics and post them on here. If Dell'Orto's are like Webers, I would go ahead and replace the damaged parts. Then replace onto the car.
Before starting the car I would check the floats of both cars to make sure they're within spec.

I would also pull the valve cover and make sure the cams are timed right, that may be a long shot but its such cheap insurance to avoid a fire :oops:
Ignition has been mentioned, ignition timing, wires/boots etc. should be inspected

@Buckaroo1! Will you be fixing the damage yourself or do you have a mechanic? I see your previous work has been done by a mechanic, personally I am a once bitten twice shy kind of guy....
 
1 - 18 of 18 Posts
Top