Overheating Problems

I run my boat in 100+ degree temps all the time and the engine temp is the same as it is in cooler temps.  Also, when I lived in the Lake Meadows subdivision and ran my boat on Boone Lake I never had a problem either! 

Doghouse = engine cover

Long time lurker, but finally created an account. I am still learning how to post, so please forgive me if this is not the correct way. I have searched all over the forum and cannot find someone with my exact problem. To start from the beginning, I have a 1984 Ski Nautique with a 351W. I bought the boat from a friend in March, 2020 with 323 original hours. The boat is in great shape and ran well the first few times I put it in the water. When the weather got hot here in Tennessee (roughly July), the boat started getting to about 180 and and would sputter like it was not getting fuel. After a couple of minutes of running rough, the boat would die and would not start for 30 minutes to an hour of sitting. It would try to turn over, but once again it acted like it was not getting any fuel. After sitting, the boat would start right back up and run fine the remainder of the day. 

Taking opinions from other Nautique owners, and posts from CCF, I tried preventative things that I thought could be causing the issue: New carb, new coil, impeller, installing fan under doghouse to try and keep it cool. After all that, I struggled with the same issue throughout all last year. At the end of last year, I took it to a local boat mechanic who is familiar with older Nautiques. He sent me many videos of the boat going up and down the lake with no issues at all. He could not get the boat to replicate any of my problems. This was the last time my boat was used for the year before being winterized. 

Fast forward to this year. I put my boat in the water and it ran fine on the first two occasions. Roughly 65 and 70 degree days. I thought all my issues were gone. The third time I took it out, the outside temperature was 87 degrees and it did the same thing once again. It got hot, started running rough, then died and would not start back until it sat for about an hour. One of my friends mentioned that my doghouse had no vents like his matercraft, and maybe it was getting too hot under the doghouse. So at this point I was willing to try anything. I took the dog house completely off and the boat ran fine and stayed  at 160 degrees all day. I tried it two more times with no doghouse and it still ran perfect. Both were very hot days. I initially thought that maybe the vent coming from the hood cowl was clogged/rotten so it was not getting air, however, other posts suggest that is mostly for gas fumes. 

I am sorry for the long post! This is a very long winded way of me asking, is this just a coincidence or should I cut some vents into my doghouse? Other things I should look at or suggestions?

Thank you!