using 25v power supply with L298 h-bridge and 2 gear motors

hello guys

actually, I'm working on a project that contains 2x(12v gear motors )

I connected them to L298 H-bridge board and then to Arduino

I tested them working both at a time (knowing that I connected a 12v power supply to the module)
and they seem a bit slower and that because each motor needs 12v

so I decided to connect a 25v power supply to the module instead of 12v, and I know that I should remove the jumper when using more than 12v

the problem is, whenever I remove the jumper the module turns off, but as soon as I put back, it works , but I can't leave like that because it will burn the regulator ..right?

is there anything I can do?

thanks in advanced

Without the jumper you will have to supply the module with 5 volt logic power from somewhere, I won't suggest your Arduino without knowing more about that particular module, can you post a link and or picture? Also, what is 25V going to do to your 12V motors?
EDIT: If your 12V supply cannot hold up 12V with both motors, best solution is a more powerful 12V supply. And don't forget, the L298 is going to drop 1 or 2 volts depending on current draw, if you get 11V to a motor you're doing OK.

this is the picture of the module I am using :

and this a picture of the type of motors used on the project:

I want to use 25v so that each motor operate at its full capability
because there is a 3v drop when each motor operate, and their movement is not stable enough as I can tell

but since you suggested using a powerful 12v power supply I will try that

Stall current of that motor seems to be 1.2Amp@12volt.
Make sure the supply can provide that current.

The L298 drops indeed a few volts in H-bridge mode.
You could compensate for that with the supply,
but I don't think a motor made for 12volt is going to survive 25volt for long.

Just be sure not to use more than 50% PWM {analogWrite(motorPin, 128);} for more than a few seconds or the motor will overheat.

A 5V power converter from Pololu will easily handle 25V input and give you good power for the Arduino.