So I got my new exhaust system on my boat and everything is ready to go, I turn the water on and start the motor and shortly thereafter discover there is no water coming out the exhaust. I've checked all the hoses for blockage, took the sea water pump apart, the impeller was fine, checked the sea strainer. Any Ideas on why I wasn't pumping water? The boat sat for about 6 months and in that time the block was drained to replace the heads. It's a TRS small block setup where water goes through the bellhousing. Thanks for any input.
Dave

After I winterize my boat, and drain everything, it can take many seconds for the water to fill the block and come out the exhaust.

Did you perhaps not wait long enough? If your seawater pump is working at all, it should eventually come out the exhaust, unless there is a major problem going on...

I would give it up to 20-30 seconds. If still nothing, then check all hoses...
Kent

When I start one up I always watch the ingoing water to make sure its stopped leaking all over. This indicated the pump is drawing the water in. If pump is spinning and water is still leaking all over, something is wrong.

BT

On more than one occasion I've had impellers that are still in-tact but they just won't draw water. The rubber, especially after sitting, loses strength. When replacing the impeller I would suggest using a genuine Mercruiser impeller. There's a coupler of after market impellers available, but I've never had good luck with them. I've taken new Brand X impellers out of the bag, installed them and they won't draw or they draw slow, replace it with a Merc impeller and it works perfect.

Thanks guys,
I know I didn't wait 30 seconds because I didn't want to burn out the impeller so I'm going to replace it anyway and prime the system before starting it and try again. Has anyone tried one of those new sea water pump brackets that supposedly simplifies it. (the one that doesen't wrap under the harmonic balancer)

I had the same problem a couple years ago. Still not exactly what happened but after taking the sea water pump apart to check the impeller to find everything looked fine I was perplexed. Prior to starting the engine the second time I held the water supply muffs very tightly against the water pick ups on the outdrive. I held them there for approx. 30 seconds (with water running) in hopes of filling all water passages/hoses between the outdrive and sea water pump. It worked this time!! Maybe an air lock or lack of enough water on the supply side to start pumping?? Maybe not?? Good luck.

Too Old,
That replaces stock Merc stuff?

Are replacement impellers readily available for these pumps? Any word on the rotation flows? Same each way?

BT