Four blade props would help a lot. Also make sure your drives are trimming up evenly.

BT

Sounds like you answered your own question...if your sync tach is even and your right tach shows a higher rpm than your left then that would explain why your boat is wanting to turn. Just try using your tachs and not the sync tach. My bet is your boat will go straight if both engines are turning the same rpm. The sync tach can be adjusted if it is reading incorrectly.

Got back from a weekend on the water and I brought the boat home. Both props are solid hubs and the look fine. I belive that I will have these seviced and checked out anyway. Also while trying to figure out my problem I tried running by the tach's and did not make alot of difference and the engines did not sound like they were in sync. One other thing, when idleing put the starb eng in gear and it has more thrust than the port side at idle. While underway boat pulls to the port. Could I have 2 different gear ratio's or problems in outdrive ?
thanks for everyones help