i have #5ssm drives and filled them to the upper plug...replaced the plug and remove the cap in the transom plate and filled it to the half way mark in the sight glass....would this cause me to loose rpm?

A #3-4-5 should actually have nothing in the resorvior..if u fill the drive from the bottom untill u can just see it in the res. then u need to stop. otherwise u will have a mess in the bildge !!!

Loosing rpm, NO...if the drive is full its full !!!!!!!

only one way to findout i guess......