exhaust water flow question

[capz]

I just pulled the boat for the winter and I think something is not right with the cooling system. First thing I did was pull the thermostat and reinstalled the housing without the new stat. Then I put on muffs to flush the engine. I started it up and noticed there was no water coming out the prop. There was a small amount spurting out the port and starboard exhaust ports. Seems like a smoked water pump impeller but I never had a problem with overheating all summer. I put about 60 hours on the engine and the gauge never rose above 175.
So how much water should I see out the exhaust and where should I look? I know Bravo 3 has through prop exhaust but should I also see water coming out the ports under the gimbal ring?

 

[Dave S]

Water always comes out under the gimball ring on mine. Did the engine overheat on the muffs?

 

[capz]

It did not overheat according to the gauge. It showed 140 although if there's no water flowing through the thermostat housing that's probably not accurate. So there's no water coming out I guess I have to assume there's none coming in. I'll blow out the lines to the manifolds first to test for blockage but I really think it's the pump. Got some work to do in the spring.

 

[Alex F]

Have you trie raising RPMs a little to force the circulation?

 

[jg300da]

Had the same problem with an earlier 260DA. The impeller was worn and once the boat was pulled from the water the outdrive drained and the pump lost it's prime. Test it by squeezing the muffs preventing water from spilling, that should increase the pressure long enough for the impeller to pick up it's prime again. Pretty sure you'll find a worn impeller.

 

[FYN409]

When running my alpha drive on the muffs I would say at an idle all of the water comes out of the ports under the gimbal ring, and above an idle 90% from the ports and 10% from the prop.

-Ryan

 

[capz]

Raising rpms to 1700 made no difference.

"The impeller was worn and once the boat was pulled from the water the outdrive drained and the pump lost it's prime. Test it by squeezing the muffs preventing water from spilling, that should increase the pressure long enough for the impeller to pick up it's prime again. Pretty sure you'll find a worn impeller."

That makes sense. So water will stay in the pump with an intact impeller but if it's worn it will flow out. Most likely worn, I don't think the previous owner ever had it changed so I know it was due to go. Better now than on the water.

I ran antifreeze (blue) through by pouring into the hoses on the thermostat housing and revved a few times. I did see some drip out the exhaust ports so it's not blocked. Should be good enough. Thanks for all the good info.