Mercury 150 water pump issue

[badnews88]

Alight, so i'm new around here, but i need some help.

I have a '03 mercury 150 saltwater plain-jane v-6 outboard. Not an optimax or any weird stuff. 6 cylinders, 3 carbs, nothing aftermarket.

My stream of water out the back acts like it has prostate cancer. It sputters at idle, and runs ok on plane. In easy water its nothing, but in 3-4' seas it runs hot. I have replaced the entire water pump, even the bottom piece. It did have a melted plastic housing on the bottom and the bone head who owned it before me used silicone to seal it up. But i replaced everything in the lower unit, and the water flow is still the same. short of giant chunks of rust in the block, are there any other ideas?

[Faztbullet]

Piece of previous owners silicon blocking "poppet valve" flow or in divider plate passages...

[1nebel0]

Check and or replace both thermostats. Take out the poppet valve and replace the diaphram...That takes care of the components that control water flow..I have a number of high performance Merc's and none of them pee strong except my 90h.p. which uses a big impeller like Johnson's do...The 150 uses a small impeller and it causes 1-2 lbs at idle and 10-14 lbs at full throttle.. Get yourself a pressure gauge so you know what the pressure is. Many guys have a temp gauge as well.. You should have the alarm on the controller and it it is running hot should be sounding...How do you know it's hot in 2-3ft seas..We need more information to dial you in....

[spicoastie]

Alight, so i'm new around here, but i need some help.

I have a '03 mercury 150 saltwater plain-jane v-6 outboard. Not an optimax or any weird stuff. 6 cylinders, 3 carbs, nothing aftermarket.

My stream of water out the back acts like it has prostate cancer. It sputters at idle, and runs ok on plane. In easy water its nothing, but in 3-4' seas it runs hot. I have replaced the entire water pump, even the bottom piece. It did have a melted plastic housing on the bottom and the bone head who owned it before me used silicone to seal it up. But i replaced everything in the lower unit, and the water flow is still the same. short of giant chunks of rust in the block, are there any other ideas?

There is two water pumps for that engine one with a plastic housing and the other is metal. The problem with the plastic housing is that when it gets hot it expands and the impellar can loose prime. Go to your local dealer and see if they can get you the metal housing its the same part number as the plastic one but with i think T01 on the end make sure they find out because there parts list will only give the part number for the plastic one

Hope this helps

Brett