I have a 225 promax that was originally a 260. The previous owner blew up the 260 and dropped the 225 on the 1 piece exhaust adapter plate. It was still setup like the 260 with no thermostats and with washers instead. It runs 140-150 cruising, but as soon as you drop back to idle, it drops to100 or less, depending on lake temp. I'm going to switch to the 2 piece plate to maintain temperature better. It loads up some at idle probably because the acu is seeing cold engine temps. I was just wondering if with the factory cooling setup, for the steel sleeve 225 ,if it maintains temperature with different lake water temps before I change the exhaust plate. Thanks for the reply.