Venus Felsa 751, low rate after servicing

Dear Omega friends,

I have been restoring a Venus with Felsa cal.751 and while I get all the readings in the timegrapher satisfactory, I can't set the rate to go more than -180 sec/day.
When the regulator pin is at middle of he balance bridge I get around -700 sec/day and at the most advance position I can set it the reading is around -180 sec/day.
The movement has been cleaned thoroughly and inspected and all seemed fine.

Any opinions anyone?

Thanks in advance.

Do you have the lift angle set correctly as 332 degrees amplitude is high?

If it's running slow:
Did it run OK before you serviced it?
Did you change the balance or hairspring?
Is the regulator pin gap reasonable?
Is the hairspring between the regulator pins correctly?

This could be a lot of things so, check it as Jim says and see if it behaves at lower amplitude.

Cheers, Chris

Thank you all for your replies,
To answer Chris's questions, the watch was running before service but the readings were erratic.
I have checked multiple times everything that has to do with the balance and the hairspring and didn't find anything abnormal.
I let the mainspring down and gave it power slowly as JimInOz said but again no difference.
Finally today I inspected more closely the pallet fork and I think I found the cause of this problem.
One of the pallet stones is broken on one side ( I missed that on my primary inspection🙁)
Parts are already on their way so I will update once I receive them.