I sucked up some MAJOR sand last weekend and tried to back flush things the best I could and replaced the impeller pump. There was like 2 whole cups of sand that came out!!! It runs fine...160-180 at an idle or even 2000rpm's but once you open it up it overheats. And the other engine is fine I ran it pretty long and it weas good except it would go from 170'is down to 110 out of no where (fauilty guage maybe?) Any suggestions? This really sucks! Also, at no wake speed the steering vibrates the whole boat ma little....????
Thanks alot Boats a 2000 33 Outlaw with 502'MPI's

Thermostat cloked up ,,but steering ?????

You need to remove every hose and flush out every section you can separately to make sure all the sand is out. After that remove the engine drain plugs and run the engine on the hose with plugs out.

Then do teh same on the other engine. Even though you think its fine, You will most likely have quite a bit of sand in it as well.

It sucks to do, but you'll be better off to get as much sand out as you can now.

With the engine running turn the steering slowly lock to lock several times to purge air from the system. Make sure the fluid level is topped off. Also it sound like you need to replace the seawater pumps.

?????