What prop are you running? tempest or fury?

Tempest plus, it was on my first Caymas. I have a merc now.

Unfortunately , alot of these problems are a result of cheap part supply issues that have come down the pipe with inferior metals and such. It's a problem in all areas that's showing up every where. Props that sling blades etc, but all the manufacturers say there not at all the problem, now it's user error. Buy a 600 prop now and it's a 50 /50 chance you get one that lasts. Ask a welder what they think of the material they have to work with today and if it's comparable to even 5 years ago.

90 percent of my 50 thrust washers I’ve replaced this year already is due to heat related issues. Hydraulic jackplates sell most of the thrust washers. Yamaha stuff is designed to run down in the water. U will need to swap to a Merc prop and thrust washer setup to run ur motor high. Granted the slinging of prop blades is kinda on that same running to high and coming out water. But there is a issue with them cracking the hubs on the T-2 props

The SHO lower unit design probably does not help this overheating issue mentioned above either. Pretty much every one I have ever checked that is over about 25 hours of run time past a service is at least a little low on gear oil. That lower unit slowly blows out oil over time. It doesn't let any water in but it sure lets oil out. It has to happen when the motor is running because I have never seen one drip oil while being stored. I've asked Yamaha about this and they say it is normal. Something about the way the seals are designed basically backwards of the way they once did them. I won't run mine more than 30 hours or so without topping it off. If you are waiting until your 100hr service to look at your gear oil I can promise you that gear case is low and running way hotter than it should be. I've seen multiple guys pulling 250 SHO motors out of the water in the summer with the lower units steaming. Both times they were right at their 100 hour service and very very low on gear oil. Personally I have not seen the thrust washer issue on my rig, and I'm not saying this is causing them to fail, but it may be a contributing factor to the issue.

Are you using the Yamaha two piece thrust washer assy.? We haven't seen an failures with this set up.