hydraulic motor

looking to put a hydraulic motor on a winch, my pump puts out 6.3 gallon per minute, the pump i'm looking at is rated at 10.5 GPM. and turns out 10 horse power, what will happen by putting 6.3 GPM into it,..??????

will run a little over half speed.

Look at pressures so you know if it will supply enough torque

I assume you mean the MOTOR you're looking at is rated at 10.5 GPM, not the pump. It'll run about 60% of it's rated speed, make sure that the motor you're looking at is able to deal with "equal to" or "greater than" pressure than your pump will create.

It will be "Half Fast".

Most electric winches seem to be no more than 1 1/2 horsepower. Six GPM at 2000 PSI is about 6 HP. I have had and have been very happy with hydraulic powered winches.

FLOW, in gallons per minute, equals speed or RPM,
the more flow the faster the motor will run, up
to it"s rated input. If you try to put more volume into it than what it"s rated for, it will
still work but trying to squeeze in extra flow
will cause it to heat up. If you put less gallons
per minute of flow into it than it"s rated it
will just run slower. If pressure is the same, it
will still have the same power-just at a slower
RPM.
Pressure, in Pounds per square inch,(PSI) equals
twisting power or torque, less pressure is less
power ! Exceeding the manufacturers pressure
rating could cause the motor to blow seals.
Check your motor manufacturers ratings, it will
have a Displacement rating or cubic inch"s of oil
per RPM, or how much oil is needed to turn 1 RPM.
multiply that by the desired RPM to get the volume of oil needed to turn the desired RPM.
There are 231 cubic inches in a gallon. Divide
your cubic inchs by 231 and you have the gallons
per minute needed (in pump size) to run the motor
the desired RPM.
Your motor will have a "Torque rating" at a
certain pressure..say XXX inch pounds at 1000PSI,
(Do that by 1.5 if you are going to need 1500 PSI
etc.) Torque times RPM divided by 63025 equals
horsepower. T x RPM /63025 = HP