You didn't say which series core
pak you have. Raymarine and presumably Autohelm
had three types with progressively greater output current
capability; S1, S2 and S3. If you have S2 you are good. If you have S1 maybe not so good.
I say maybe because the current
that the heavier linear drive will draw depends on the boat, its steering gear
and the wind
conditions. If you don't put any heavier load on the new unit than you did on the old, you should be fine as the current draw will be approximately the same. But the new unit will draw more current if it sees a greater resistance and that may be the problem.