Impeller woes.

Hammerhead

Hammerhead

Senior Member
The other day, I wanted to but.,couldn't go out on the water. I figured I'd burn the gas at least out of the carb while it sat on the trailer. I hooked up the ears,..started the boat. It ran at idle fine. Then I noticed a whirling noise. Then smelled,..Rubber???
Looked over the aft..Holy moly,..I DIDN't turn the water on. I hopped overboard to do that hoping It'd cool the impeller down plus the motor was now getting hot !!! AAARRGGHHHH.
Yesterday I took it out for a test and sure nuff it was running hot by about 20 degrees or so,..@190. There's water blowing outta the exhaust but, I think I gotta change it. Any thoughts?

Like I don't hava nuff to do,...this goes to the front burner.
Never changed one before. Any tricks if I do? It's a '77 merc-cruiser i/o TIA
 
I've changed one on an I/O Merc.
The only thing I remember was the shift dog had to be in a certain position but can't remember what position it needed to be in. Seems like it was full reverse but don't take it as the Gospel.
Every thing else seemed to be the same as any other foot.

Get more opinions.
 
Yep, its cooked! I did almost the same thing a few years ago. I was working on the 170 merc, setting the timing and carb adjustments and had the hose kinked while I made some changes and forgot to unkink it and fried my water pump. You probley need to change the whole waterpump( top cover, impeller and lower half housing). It only takes about 20 seconds to melt a dry impeller and it usually warps the top and bottom pump housing. Sorry! Just drop the lower unit, disassemble the complete pump down to the bottom of the case and replace all gaskets and lower pump housing. Then stick the impeller key to the shaft. Take the impeller and turn it lefthanded into the top housing and slide down onto the shaft. Be sure the key stays in place! Bolt it all back up and you're good ta go. It really easy. The kit usually cost about 46 bucks and about 20.00 for the bottom housing. Take my word for it, REPLACE THE LOWER HOUSING!! Good luck. A manual really helps out alot.
 
Yep, make sure it's in forward and also pay attention to the small seal that goes in between the upper and lower that seals the oil passage. It is easy to overlook, but it must be kept intact and should be replaced when doing the pump. Also make sure and do a complete pump kit with base since it got hot. You don't want to chance the extra $20 or so and have the base be bad.
 
I found it much easier to re-install the lower unit when using a a cargo strap to lift and hold it in place
 

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Thanks guys.
It's been running so good of late I won't mind getting a lil'dirty.Besides,..
That's half the fun?,....ain't it? or was I lied to when I bought it???
 
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