water pressure problems DT225

[BayChampman]

6 times in the shop for water pressure problems!!!
2003 DT225
The warning horn comes on and the engine rolls back down and the overheat light comes on. This problem only occurs from 3800-4200 RPMs! Water pressure is at about 15 psi or so. Water pump has been changed twice. Thermostats have been changed along with the sensors. Motor runs fine above the rpm or below it! While running with the Dyno hooked up it will not do it! Its been in the Suzuki dealer twice and they changed most of the parts listed above. Another shop changed the other parts and hooked it up to the dyno. The port side head appears to be running a little warmer than the other head. Motor will run 5500 rpm for on a trip for 10 miles and not have any signs of overhead and the water pump appears to be pumping alot of water out. After all the trips to the shop I am at Wits end! Any help will be appreciated!
Thanks,
BayChampman

[Brews_N_Bass]

I read that if the thermostats have been changed to 150° from the 140° you will need to put in the resistor upgrade on the temperature sensors. This should solve the problem. Read this on one of the suzuki owners forums. Also decarbon the engine with seafoam was suggested too.

[Tim Kelly]

I remember on one of those Team Marine you tube videos they changed the water intake screens to a set from a 300 to improve cooling. Don't know if it applies to your motor though?

[ampdreamer1]

Also seen you can buy the water intake filters or vents at bottom of engine on each side for a 300hp model and they fit right in letting better water flow

[ampdreamer1]

Oop just seen the guy before me said the same thing. Lol