Flat spot when in third accelerating from a corner. What could be the problem?

[Lynden]

Hi, I have a 74 Lancia Beta sedan 1.8. It has not been on the road since 07, Was one owner from 74 until 07 with service history.  I bought it in 2010 and finally it is now road registered after removing minimal rust, underneath was rust free, and a respray. Have replaced timing belt, points and plugs, etc. Have noticed that when accelerating from a corner in third gear there is a flat spot, otherwise appears to be running fine. What could be causing this to happen? Any ideas would be greatly appreciated.

Cheers
Lynden

[peteracs]

Hi

Have you cleaned out the fuel filters/carb and checked tank for crud? (I am assuming it is a carb model)

Peter

[rossocorsa]

I would completely remove and dismantle the carb to clean and blow through with compressed air, also change the rubber diaphragms not difficult so long as you are careful and methodical and assuming it hasn't seen any attention for years will probably do the trick

[Lynden]

Thanks guys. Will check it out.

[Neil-yaj396]

This is a good thread to read re carburetor issues;

http://www.betaboyz.myzen.co.uk/forum/index.php?topic=649.0

As per the thread my car had all sorts of fuel related running issues. Rossocorsa's suggestion is the only real solution, but often you can't actually see anything visibly wrong inside the carb.

[droptop]

I agree wholeheartedly.
When I recomissioned my spider after it was laid up from 1988 until 2010, I neglected to clean the carb, the result of which was to have the car die on the side of a "b" road in the dark!
the lucky thing was that it happened outside the house of one of the most obliging people I ever met who came out to see what was going on, then set up an airline from a compressor in his shed, provided me with tools and we dismantled the carb and blew the jets out, removed the filter in the actual carb and cleaned years of crud out of it as well.
lLsson learned!

Also, when I fitted a new fuel filter, i fitted it between the steel fuel line and the incoming side of the fuel pump as some pumps have a gauze in them which can clog with dirt and then fail to deliver to the carb.

The filter I used is one with a removable, cleanable bronze element and I clean it after every run.
It's slim, neat, easy to fit and aesthetically pleasing as opposed to one of those transparent plastic yokes hanging suspended between the fuel pump and the carb.

At  this stage, very little, if any, dirt shows up in it as the tank seems to have given up all the residual debris.

I should mention that the rubber sections of the feed and return fuel lines all had to be replaced as they systematically went porous as each preceeding one was replaced, including the lines from the tank to the lines at the rear of the car.

It's a low cost, high reward job which not only stops leaks and unnecessary fuel loss, but stops fumes and reduces the risk of fire so I consider the lines and filter, along with new hose clips, twenty quid well spent