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Lower unit stuck, 1974 Merc 20hp

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DaubsNU1

New member
Engine fired right up after sitting for 10+ years, but water pump not "peeing" so I shut her right down.

Removed the two bolts and I am trying to get the lower unit off to access the water pump.

It is stuck.

I can drive flat screwdrivers between lower and upper unit...the front side (towards front of engine) seems to open about 1/8", but the rear won't budge.

I don't want to mess anything up...

Suggestions to get the lower unit off?

Thanks!
 
Great advice! Yes, there was another bolt under the trim tab. Got it off, and got the lower unit separated.

Now my problem is this...

I cannot get the water impeller off of the drive shaft. It seems to be rusted on there. I've tried penetrating oil...it just won't budge.

Suggesions?
 
Make sure shaft isn't too rusty at the seal there just below water pump. How does the lower unit oil look?
 
Using air compressor, blew air in to the tube in lower unit...and felt air coming out the "pee hole." Looks to be free and clear. Once I get parts I will re-assemble and test in water.

One question for you: The stock impeller (that I took off the engine), had curved vanes. The replacement looks to have straight vanes. I've seen Youtube videos where guys suggest curving the vanes forward, then installing cover. True?
 
Right....install into pump chamber turning clockwise looking from top ......or in other words, counter clockwise looking from bottom. As you tighten down pump housing, make sure tips of impeller don't get pinched between housing and plate. I lube with little silicone or similar product to aide in start up.
 
timguy said:
right....install into pump chamber turning clockwise looking from top ......or in other words, counter clockwise looking from bottom. As you tighten down pump housing, make sure tips of impeller don't get pinched between housing and plate. I lube with little silicone or similar product to aide in start up.
Click to expand...

thanks!
 
Thanks for all the wisdom. Water impeller installed. Had trouble getting the lower unit back on...then when it was on I had the gears wrong...had to take lower unit off again.

It's all together now, and the gears are shifting as they should -- forward, neutral, reverse. I'm going to test it out tonight and make sure the water pump is making the engine "pee." Wish me luck.
 
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