Twin Solex pa44 1, volvo penta Aq151B

[stresspoint]

wait ! , if it was as you say running fine before you did the carb.????? why would the timing be wrong .
concentrate on getting the carbs sorted , then if need be mess with timing.

 

[kenny nunez]

After you replace the timing belt remove the spark plugs and spin the engine with the starter or with a wrench a few times to check if the timing marks on the belt “walk” back to the original location when you first installed it. It take around 25 revoloutions to get the marks back to the starting point. Do not be surprised if they do not line up, this happens when the tensioner is released.
It might run with 1 tooth off but not correctly.