Is there a way to find the current limit on the secondary side of a power transformer. Because i got one from a pcb, and want to know the current limit for a project.

 

One rough way is to load it with a resistive load until the voltage drops about 10%.
That should give you a reasonable limit for the RMS current.
The maximum DC current from a connected full-wave rectifier-capacitor filter would be about 60% of that.

 

Are there any markings on the transformer?

 

Weigh it and one similar that you know about. Then estimate using watts per pound. Measure the output voltage, reduce that number by 10% like crutschow said, and divide the watts by the voltage.

Crude, but better than a complete guess.
Then measure the temperature after you have it running something. If it's too hot to hold your hand on, you're probably wrong.