No seawater flow?

[jshack]

After winter storage, I removed the seawater pump (2004 5.0 MPI Mercruiser Bravo 3 w/ belt driven seawater pump) and replaced pump impeller, all went well, until I started engine and had no water flow. Tried everything I could think of, including priming the pump. Disconnected the pumps water inlet hose and turn on the house water connected to the lower unit, and had no water supply to the seawater pump? There are no valves between the lower unit and the pump inlet. Any ideas on what the problem could be will be greatly appreciated, thank you.

 

[Xplicitlnck]

Did you mark the hoses before you took them off the pump? Maybe you reinstalles them backwords (inlwt hose to the outlet on the pump and outlet to thw inlet on the pump) you could have either mixed up the hoses or put the pump on upside . I hink he bolt pattern would allow this. I would also replace or atleast inspect the impeller again

 

[vrcrdavi]

Hopefully you noted which way the original impeller was curved into the housing. The new should have been installed the same direction. If not, I don't think it will work.

 

[jshack]

Yes, I marked the hoses and they are two different sizes. The bolt pattern and the pump rear plate will not allow the pump to be put together incorrectly. The problem is I am not getting seawater from the lower unit to the pump so the pump has nothing to pump, thanks.

 

[jshack]

yea, I caught that, thanks.

 

[Jimmy Buoy]

Are we to assume that you are starting the motor on the "hard" using muffs? How long did you run the engine? It can take up to 45 seconds or so for water to begin exiting the exhaust. If you remove the water supply hose at the pump, is there water flow?

 

[Great lakes pirate]

With the engine off. Pull the big hose on the thermostat housing off. Put a garden hose in and fill it up with water. Now you know you have water on both sides of the impeller. Crank it over. I do this at the start of every season to prime the system.

 

[1990-270-da-lover]

If you were to remove the inlet hose from the pump and connect the muffs to the lower unit and turn on the water, you should have a pretty signifigant flow of water through that hose. If not the problem lies between the muffs and the inlet hose, possibly a clogged or kinked water inlet hose in the drive/gimbal housing. Hope all works out well.

 

[Bob & Sue]

All the above plus if your using the c-style outboard muffs they may not be supplying enough water pressure leaking around the outdrive I had that problem at the marina you want to use the 2 piece muffs that have a rod going through the water intake vents to secure them tight to the drive. Hope all goes well.

 

[kevin27]

Sounds like the water tube in the transome assy has corrosion and closed shut. Here is a picture of what I am talking about.

 

[dan313]

I had a smiliar problem. The muffs that i was using did not cover the small hole( water pick up) on front of the lower unit. You have to put a piece of duct tape over that small hole and then you should have enough water pressure going up into the lower unit. Hope this helps.