water pump question

How do you tell if the water pump is pumping? mercurser i/o 4 cy not sure what out drive I have yet .

Re: water pump question

well, one thing would be that the temp gauge shows normal operating temp.

my temp gauge don't have numbers, so i had to find out what normal was..

this reading about normal on the hose or just idling around at the lake.


this is the norm after a hard run then turned off for a bit and restarted. i believe the higher reading is due to heat soak.


as it comes right back down to a normal reading within seconds after restart.

while on the hose. it's nice to see this..

water coming out the prop hub, out the pee hole at the ft. of the bullet + water exiting both idle relief ports by the transom. if i see this while on the hose at home, i believe i'm likely to be cooling properly..

i also replace my impeller yearly. this is a first step in being sure that the cooling system is in order. it's a most neglected part that is supposed to be inspected yearly. it's most critical to keeping the engine cool.

others may have some other ways of knowing your pumping water..
best i can do for ya though.

Re: water pump question

thank you helped out alot

Re: water pump question

Hey Ziggy - I've seen you post and comment on the "pee stream" a few times. I'm curious - none of the Mercruisers I've ever had had water coming out of that hole. I thought it was just for draining any water that got into the cavity there at the front of the drive. I suppose that is all open to the exhaust.... but I've never seen one with a steady stream like that. I guess I bring it up to ask if anyone else has noticed this on their Alpha or pre-alpha?

(Hopefully this isn't highjacking the thread. Just following along with the idea of a "tell tale" for the pump).

Re: water pump question

Fishermark said:

Hey Ziggy - I've seen you post and comment on the "pee stream" a few times. I'm curious - none of the Mercruisers I've ever had had water coming out of that hole. I thought it was just for draining any water that got into the cavity there at the front of the drive. I suppose that is all open to the exhaust.... but I've never seen one with a steady stream like that. I guess I bring it up to ask if anyone else has noticed this on their Alpha or pre-alpha?

(Hopefully this isn't highjacking the thread. Just following along with the idea of a "tell tale" for the pump).

Click to expand...

Since my dad is the owner of the boat but I use it more than he does, our mercruiser is the same way as yours doesn't have water come out of the hole when on the hose.

Re: water pump question

Water comes out of that hole on mine on muffs. Not sure if that's good or bad or it means nothing?

(alpha I gen 1)