Mercury 2001 O/B 50ELPT impeller parts have gone in to engine block

[Trader Vick]

My merc 4-stoke "small"foot  (SERIAL # 0T229967) has had impeller fail, (7 months old !) new one installed but engine not cooling at higher RPM. Further, when engine is turned off, a gurgling sound can be heard from upper exhaust port as water leaves block. So it seems there are a few impeller pieces in the cooling passages of the block. How big a deal is it to get to those, I  know some engine dismantle is in order, not sure what I will be in for, can't find diagram of cooling passages and any videos of the job.

 

[yzf125]

Look through this manual to help you out >> http://boatinfo.no/lib/mercury/manuals/40-50-60_02.html#/0

 

[CharlieB]

Cooling flow generally passes up thru the exhaust side cover first so to keep it cool enough you can hold your hand against it while running. Impeller pieces commonly lodge in small passages there.

Be very careful removing exhaust cover bolts, they can sieze and break off easily. Beat, rappedly with a very small hammer while attempting to turn with a hand wrench. Don't beat it trying to bend it, sharp taps to help break any corrosion in the threads while turning it with the wrench.

The side cover is actually two covers, an inner that directs exh flow and the outer that sandwiches water between the two keeping the inner cover from melting down. Make sure all surfaces are clean and flat, no warp and no holes corroded through it. Use new gaskets with very little or no sealant added. Torque carefully and patterned inside out in enlarging circles until complete.

 

[Trader Vick]

OK SO i FINALLY got to remove the exhaust cover, bolts came off ok, found no bits of impeller rubber. no corosion,I flushed it backwards wiith hose (lower unit off) thermostat clean, and new, re assemble and start. While it is running at high Idle, no overheat horn anymore, but when I shut it off, it keeps peeing. I timed it 20 seconds after key off, a decent stream too, not drips.it never did htat before. How is that even possible?

 

[GA_Boater]

Drop the lower unit again (Know you wanted to hear that) and make sure the water tube from the pump housing to the bottom of the motor is clear.

Oh - Are you running on muffs and is the water is still on? My older Merc will pee with the hose on.

 

[Trader Vick]

Running in the water, (not muffs) what is a good way to check that tube, I tried shining a light up there and looking, even used a cellphone camera aimed up to video, but cant see very well. I could maybe use a coat hanger, ( but don't want to shove any partial clog up any further !. ) that tube does let a LOT of water UP it, as plenty of HOT water comes out through the prop hub)

 

[GA_Boater]

Don't know about newer Mercs, but when my lower is dropped the tube comes out with it half the time. It has a slip seal on top just like the pump housing.