I'm gonna pick up some lower unit oil tomorrow so I can change it out on my 40 horse mercury force. How many ounces would y'all think I need? (i've looked all over the internet but cant find anything). Thanks.
My 120hp Force takes less than a quart. Buy a quart and you will have plenty. Make sure to buy the little pump that screws onto the oil bottle and pump it into the bottom fill hole till it runs out the top hole. I also like to put a little in the top first to kind of rinse the old fluid sticking to the parts inside. It always pushed out a few extra ounces of old fluid that way.