15 hp Prop shaft seal replacement help

I have a fairly new ( less than 1 year )15hp 2 stroke Yamaha and I noticed a small oil stain/drip on the lower blade of the prop when it was up on a hoist. I'm petty sure it is coming from around the shaft. How difficult is it to remove the old seal and install a new one. I am in a remote area a Fiji and mechanics are few and far between. I am pretty handy with tools but have no bearing pullers or tools like that.

I can order the parts from the states and they will get to me in only a month or two!!

I won't be able to check the oil f few days when I hoist the motor onto a deck stand.

thanks in advance

I forgot to say that it is a model number 15 FMH and I bought it in New Zealand. I hope US model parts are compatible.

thaks again

This is likely normal on a 2 stroke motor.