Boat bogs and overheats on acceleration

[Sheriff007]

Hi all looking for some help
im a new boat owner and have a 2002 Mercruiser. 8 cylinder 260 hp Bravo 3.
boat runs great at wot but if I increase speed to quickly it bogs and overheats. If i increase speed slow there is no problem. Ive only had alarm go of twice since now I keep my eye on gauge. Did compression test and all cylinders read at 150. Any suggestions on what i should be looking at.

 

[Luv2fish36]

For the bogging I'd Spin off the fuel/water separator what's in it? make sure fuel is good and theres no water in it. Check for vacuum leaks around the carb, check the timing, check your fuel pump, check your tank pickup tube and anti siphon valve, assuming its carbureted, is this a two barrel mercarb or 4b weber? check the carb out, a bad accelerator pump or bore can make it bog. Make sure the bore is not pitted out.

for the overheating. I'd start at the seawater pump 1st. Dont just look at the impeller, look at the housing the impeller rides in and if its grooved Replace both.

Is this freshwater cooled? I'd take the end caps off the heat exchanger blow the tubes out with air and shine a flashlight through. Any clogged tubes?

if its raw water cooled. I'd check the thermostat make sure its opening up. check the thermostat housing make sure it doesn't have blockages.

check the water circ pump. Take the belt off turn by hand is it rough? Also theres a weep hole on top of the circ pump. Is there weepage?

Check the inner transom water hose connection fitting. Good chance its collapsed itself. 2002 its probably time. Especially if ran in saltwater.

check the manifolds and risers.

 

[Sheriff007]

Its a 2 barrel carb. Had impeller checked last month it was good. Temp gauge only spikes when i go from a crawl to quick acceleration maybe half throttle.. Thats when it also boggs down. Slow acceleration it is fine and can get to wot.

 

[kulle]

For what it's worth....I found this water shutter in my exhaust port when i am changing bellows. I'd like to think if it broke and got stuck or clogged any part of the exhaust it could cause overheating?

 

[Sheriff007]

So checked out boat today and found a wire not plugged into carborator. Not sure if I accidentally unplugged it but dont see how since it clips together. Looks like some kind of sensor plugged it back together.
also added 2 cans of Sea Foam to gas tank.
Took it out for a ride ran great wot at 4200 rpm and accelerated fine to bogging or overheating even on quick acceleration. So atleast fo now all is good.

 

[Sheriff007]

[No message]

 

[Sheriff007]

What is the plug on the left of above photo. That is what was unplugged on my carb. Im guessing electric choke or fuel sensor.