Raw Water Pump Mistery

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   I have a problem that's driving me crazy - maybe one of you can tell me what could be wrong.

I have a new, rebuilt engine that I purchased from Bill Layton.  I installed the engine and it runs fine.  However, I can't get the raw-water system pumping and I've burned up one impeller trying.  

The pump that came with the engine, presumably installed by Bill, looks new.  It's defiantly installed correctly, the impeller turns in the correct direction (CCW) and the hoses are connected correctly.  I know the suction hoses are all clear to the through hull.  I pulled the outlet side house off the pump and was easily able to blow air in.  

I pulled the pump outlet hose off the top of the engine and sucked water easily up to that point.  I then closed the seacock and blew as hard as I could and can find no sign of a leak.  I then sucked as hard as I could, so my lips were 'stuck' to the end of the hose, and the vacuum held.  I don't think I'm sucking air. 

With water pulled up to the end of the outlet hose, I reinstalled the hose to the thermostat housing cover and opened the seacock.  Started the engine but no water is coming out of the exhaust.  The water pump housing quickly got hot to the touch so I know the impeller's turning inside. 

I'm not a diesel mechanic, but I'm not stupid either.  I've replaced the water pump before (on the old engine) and I've had my engine out before and reinstalled without any problems.

Any thoughts?     

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
khardy Members Profile Send Private Message Find Members Posts Add to Buddy List Commodore Joined: 22 June 2004 Location: United States Status: Offline Points: 132	Post Options Post Reply Quote khardy Report Post Thanks(0) Quote Reply Topic: Raw Water Pump Mistery Posted: 24 April 2019 at 10:35am
	I have a problem that's driving me crazy - maybe one of you can tell me what could be wrong. I have a new, rebuilt engine that I purchased from Bill Layton. I installed the engine and it runs fine. However, I can't get the raw-water system pumping and I've burned up one impeller trying. The pump that came with the engine, presumably installed by Bill, looks new. It's defiantly installed correctly, the impeller turns in the correct direction (CCW) and the hoses are connected correctly. I know the suction hoses are all clear to the through hull. I pulled the outlet side house off the pump and was easily able to blow air in. I pulled the pump outlet hose off the top of the engine and sucked water easily up to that point. I then closed the seacock and blew as hard as I could and can find no sign of a leak. I then sucked as hard as I could, so my lips were 'stuck' to the end of the hose, and the vacuum held. I don't think I'm sucking air. With water pulled up to the end of the outlet hose, I reinstalled the hose to the thermostat housing cover and opened the seacock. Started the engine but no water is coming out of the exhaust. The water pump housing quickly got hot to the touch so I know the impeller's turning inside. I'm not a diesel mechanic, but I'm not stupid either. I've replaced the water pump before (on the old engine) and I've had my engine out before and reinstalled without any problems. Any thoughts?

Bill Layton Members Profile Send Private Message Find Members Posts Add to Buddy List Commodore Joined: 15 September 2002 Location: Canada Status: Offline Points: 551	Post Options Post Reply Quote Bill Layton Report Post Thanks(0) Quote Reply Posted: 24 April 2019 at 11:13am
	Actually on second thought to test the muffler you would be best to take the hose off the port side of the thermostat housing that leads to the exhaust manifold and blow in that hose to see if anything comes out the muffler. You'll probably have to remove the exhaust hose from the muffler. Also be sure exhaust valve is closed on compression stroke as the air you blow will go thru the exhaust valve if not closed. Edited by Bill Layton - 24 April 2019 at 11:18am

khardy Members Profile Send Private Message Find Members Posts Add to Buddy List Commodore Joined: 22 June 2004 Location: United States Status: Offline Points: 132	Post Options Post Reply Quote khardy Report Post Thanks(0) Quote Reply Posted: 24 April 2019 at 11:22am
	Thanks for the suggestions Bill. I will give that a try, though I doubt the muffler is blocked. Exhaust comes out the muffler the few moments I run the engine. Also, when I got your engine I very carefully cleaned the old plastic muffler from my old engine and installed it on yours. While cleaning nothing seemed amiss. I also plan to remove the hose from the exhaust elbow, run the engine briefly, and see if water comes out.

Bill Layton Members Profile Send Private Message Find Members Posts Add to Buddy List Commodore Joined: 15 September 2002 Location: Canada Status: Offline Points: 551	Post Options Post Reply Quote Bill Layton Report Post Thanks(0) Quote Reply Posted: 24 April 2019 at 12:16pm
	The internal baffles can and do melt and this can allow exhaust to get out while blocking the water. It is a waterlock muffler. Unfortunately when this happens it's all internal and not visible on the outside of the muffler. Also there is a cumulative effect when running the engine without water coming out. It can take a few times to melt the baffles yet it'll run fine until it doesn't. Your not the original owner and you just melted an impeller. Due to these reasons I would suggest there is a strong possibility of melted baffles in the interior of your muffler.