1989 donzi the boat was working fine its a new engine 4 months old it just started overheating i took off the risers from the manifold and clean them replace new gaskets and its still overheating. i then pulled one of the hoses from the manifold and started the engine i get no water coming out from manifold or hose. what is the problem can anyone help plz. im also running it without a thermostat but dont think that's the reason for overheating. help...

I would say start with the sea water pump, also if it has a fresh water flush system make sure the spring inside is working it can get stuck closed.

it's only a raw water system.... but the impeller was changed 4 months ago. i dont know what to do i start the boat and in 5 mins its goes all the way up almost 200. do i need to change impeller again do they break that fast? im thinking no water is coming into the engine.

As Boomer said....1st check your sea water pump "impeller" Take your belt off turn your sea water pump pulley and if the pump turns easy both ways your impeller is toast. This is the best place to start....Good Luck!

What engine do you have?

i have a 300 hp 350 omc cobra sterndrive. i will try what you said my outdrive can tilt do i have to pull boat out water to change or it's ok?. thanks for that tip this boat got me so stress new engine and this happening.

Impeller, keep a spare on the boat, and yes you can change it right in the water. They can go out in 5 Min if ran dry or you get some junk sucked in it. I replace mine every spring before the season. Good luck

Where did you get the sea pump, you don't want the one that comes from the auto part store that also sells boat parts, use only a merc. impeller or similar quality.
I had one fail with only 10 hours on it, It takes a long time to go 25 miles with one motor.

thanks for all the info. you guys made me feel a whole lot better. i will try that but i have to wait for parts to come in i live in barbados lol. thanks again.