Quick and dirty 300 WE sea water pump impeller change

Q

QT1

Active Member
Oct 20, 2016
647
Belair, MD
Boat Info
1990 350 Sundancer, "Quality Time II".
Engines
454 Mercruisers, performance parts modified by PO.
If anyone has performed this job themselves or have an good suggestions on getting it done, please let me know. Starting here as a source of my overheating port engine yesterday. Limped back to marina on starboard engine. Thanks
 
The drives I have had with a sea water pump have been OMC or Volvo. Mercruiser has pump in the outdrive that feeds the automotive water pump on the front of the engine. Is the water inlet on the drive clear? Have you changed the thermostat? Would then look at impeller in outdrive. The sea water pump will usually has a replaceable rubber impeller in it that is replaceable but I haven't seen one on a mercruiser.
 
Going through the process of elimination, thermostat, sea strainer, seacock, impeller.
 
No outdrives
 
There are many, many threads about changing an engine-mounted raw water pump impeller on this forum. If you do a little searching, you should find plenty of info. But, yes, it can be done in the water. Sure, some water will leak in until you re-position the inlet hose (on the backside of the pump) higher than the water line and plug it for good measure. But don't panic - it won't be a huge amount. Essentially, take the pump and bracket off as a unit, remove the two hoses on the backside. Done.
 
Thanks for your input.
 
QT1 said:
If anyone has performed this job themselves or have an good suggestions on getting it done, please let me know. Starting here as a source of my overheating port engine yesterday. Limped back to marina on starboard engine. Thanks
Click to expand...
Did you check inside your heat exchanger? If it's like mine you can take the end off simply with a wrench and hose it out. Before you do buy a new gasket as mine leaked after cleaning it. Also check the water strainer for frogs or seaweed or mud.
Sorry if this is obvious, I'm new here.
 
close the seacocks to avoid any possible leakage while the hoses are off.I remove the carb studs,put old pillow on top of engine,lay long ways ontop of engine.drop arms down front of engine to take pump off engine.can do them pretty quick as I've do them every 2 years.i then replace the pump on the bench and reinstall.only a couple bolts hold it to the engine a 2 hoses on back.get complete pumps with housings and use merc stuff.
 
Thank you all for your words of wisdom! Tuesday morning is the day for the fix!
 
Well, purchased the kit with impeller, plastic cap, metal plate and bolts. Removed the entire pump made it easier job. Taking boat out to Still Pond Monday. Doing starboard pump in 2 weeks.
 
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