Raw water Strainer full of sand

BrianN15

I recently anchored at the sandy beach at the local fresh water lake.  After being out all day fired up the engines to head back to the marina.  After taking some time hovering around pulling the anchor up (due to high winds) we continued on to the marina.  Shortly thereafter I received a high temp alarm.   Once back at the dock I did some research thinking maybe the thermostat stuck open ended up buying a replacement for that.  However upon further investigation in the engine room i notice the raw water sea strainer is full.  I took off the cover and pulled out a strainer full of sand.  I was able to get this strainer empty and water running through well again.  Took the boat out the next day, boat ran fine out to the beach again (15 minute trip no overheating), anchored up everything was fine.  Went to come back to marina again and just before docking temp started to rise but never set off an alarm.  Is there a possibility some sand got by the strainer and is in the cooling system somewhere?  Last year i replaced the sea water pumps with the stainless steel Hardin pump suggested by several people in this forum.  Is there any way to flush raw water side of engine while boat in water without doing damage?  Open to all thoughts as the summer is quickly flying by.

LaRea

Yeah, you probably ingested a bunch of sand into the pump itself, and it probably chewed up the impeller and wear plates a bit.  If so, the pump would still work, but not as well as before, so the engine might run a little hotter when pushed hard.  

Next time you go out, keep a close eye on your temperatures.  If you're not overheating, running the boat won't do any further damage.  Maybe you can continue to run it until the end of the season.  At some point, you should pull the pump and install a new impeller and wear plates.  

davidbrooks

When you say you anchored at the sandy beach does that mean you ran the boat up onto the beach or that you stayed out in the deeper water with an anchor? If you beached your boat you are likely sucking up a bunch of the bottom while trying to get off of the beach.  I watch guys at the loading ramp all the time gun their engines while pushing up on a trailer and i just imagine all the junk they are sucking up just before shutting down.

BrianN15

Well it did get up to like 220 the next day while docking and just before shutting down the engine. Your thinking impeller then? Any way something could have gotten up to thermostat to make that stick.  When it originally happen, turn the engine off with the alarm, to turn back on and watch the temp drop to 170 again

BrianN15

I guess I didn’t think one instance with a sandy bottom would totally fry the impeller

LaRea

Yes, even a few minutes pumping sand can do a lot of damage.  It's mostly the wear plates.  You're lucky to have the Hardin pumps.

aero3113

If your thermostat was stuck open, your engine temp would be cooler. If it was stuck closed it would run hot. You can check it but it might be the impeller.

BrianN15

Do impellers go in clockwise or counterclockwise I have heard both

rasbury

So I always say it is crazy to do the same thing but expect a different result. If your strainer was full of sand, you were flat sucki g up some sand!

LaRea

It doesn't matter how you install the impeller.  It will right itself during the first rotation.  

rasbury

You can also install wear plates in the std merc water pump also..