carburetor problem - Alfa Romeo Bulletin Board & Forums
 
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post #1 of 2 (permalink) Old 05-26-2019, 12:52 PM Thread Starter
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carburetor problem

Hi

new engine 1750GTV 1968
weber 45dcoe
mechanical fuel pump

we started engine, set the timing to 30, engine ran fine (idle at 900/1000) and then we realised fuel pump and fuel filter are inversed (order was 1st to the filter then to the pump).
We changed the order (1st to the pump then to the fuel filter), set the timing to 36.

Then very rought idle, it raises to 4000/4500 rpm .
The car was running fine before so we decided to set back the timing to 30 but nothing changes.

The carbs are synchronized and to be sure we disconnected the linkage. Even without linkage it's going to 4000/5000 rpm at idle.

Any clues?

Thanks
Fabio Muller is offline  
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post #2 of 2 (permalink) Old 05-27-2019, 07:19 AM
High idle would normally suggest a vacuum leak. But are you sure your idle speed screw isn't turned in too much?

Regarding setting the timing, the Alfa way is to run the motor up to around 4,000 RPM and then adjust the dizzy so that the crank pointer is landing on the "M" mark on the pulley. The timing mark at idle is irrelevant...

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1750, gtv, idle, rough, weber

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