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View Full Version : Beta Coupé Carb 1300 - Fuel problems ?



Modano
18th October 2007, 03:56 AM
Hi all,

I've got an amazing 1300 double choke carb Beta Coupé since 2 years now.
I love it :)
Anyway, since the beginning I had it, I've a very very specific problems, which seems to be close to problems some people had here !!

Let's sum up things.
When running at low RPMs (< 4000), everything is okay, although the car is somewhat far from being performant. Anyway I guess the one-ton weight slows down performance :) Anyway this is not a problem.
Everything is Okay, although the motor is "coughing", and is unstable in terms of revs, when it comes to very slow revs (<1500). I have to play with the clutch to avoid aircraft-like vibrations.

But the main and real problem happens when the engine is somewhat highly in use.
What I call highly in use is :

- 4th or 5th gear only : Revs > 4000 rpm. (very common on highway)
- High rev while climbing > 4000 rpm whatever gear is chosen
- Very high rev at 3rd gear : > 5500 rpm for more than 10 seconds.

What happens is that the motor coughs, the revs drops down,and I have to pass down one gear, and calm on the throttle, (or do a good acceleration while clutch on, therefore without the engine connected), to get a normal behaviour.
On highways I cannot exceed 100 kms/h :( If I go too high on revs, problems happen.

What happened very recently is, on a highway exit, I got always the same behaviour, but I insisted a little bit and then...boum, the motor purely stalled.I got very afraid when I saw the Oil pressure light on, but Jesus I was so happy when I saw it was just a Stall. Anyway, a bit dangerous..

It took me 3 or 4 starting tries to get it back running.... When this happened, I knew this was related to fuel arrival, and not to any ignition problems (got an electronic ignition).


In parallel, since months I have another problem :

When the car does not run for 4 days, it takes aeons to start it. The fuel circuit seems to be fully empty, and I have to try 5-6-7 starts to get fuel arriving, and then the car runs very fine and starts at the first glance.
I was told there may be a leak somewhere. I cannot smell petrol anywhere in the motor compartiment. The mechanical fuel pump has been changed 1 year ago...
And when I start, in the morning, the car...I hear a liquid noise from rear to front, on the right side, near the door....exactly where the fuel circuit is located !!! May this be my fuel ?


So I heard many theories :
- leak inside the carb, which goes directly in Admission pipe ?...
- Fuel tank rusty-dirty-ugly ? My fuel filter doesnt seem to show big rust blocks at all... I tried to put some fuel in a bottle directly after the pump, it was crystal clear.
- Not a problem related to Fuel system ?
- Automatic Choke ? (I'll get rid of it very soon I guess. I suspect it to grow my comsuption by 1 liter per 100 kms...)

Note that my fuel comsuption is very high in Town, and the exhaust badly smells fuel.

Thanks a lot :)

chrisc
18th October 2007, 05:54 AM
Sounds like the problems at the carb end of things, although the original having to tweak the clutch to avoid vibrations suggests possibly you have a poorly balanced engine or flywheel?

Id start with removing the carb, cleaning it all up and fitting new gaskets and see what that does for it.

Whats it like to drive when its running right? When ive got my VX finished, and a garage to do the work myself i can see a 1300 coupe as my next project... if i can find one

Modano
23rd October 2007, 03:28 PM
Hi chrisc,
poorly balanced engine...mmm why not !

Anyway I'll do a very good cleanup + adjustements of the carb...but I'm afraid the root problem is coming from the fuel circuit...

When running right (never fully happened due to that) it is a dream.
Double choke carb, responsiveness, pleasure ..wow :D