Outboard engine Impeller Replacement

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Mr Jimmy said:
Checking one of these guys out doesn't look like changing a light bulb.
You have to drop the entire unit.
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On outboards yes but in more modern drives and a few classics you can change them without pulling the drives. I think Mercury Bravo 2's and beyond are like that and every OMC since Cobra and Volvos old and newer including SX drives can be done in the water too. I have Bravo's on my HB and not only do you have to pull the drives but it drops its fluid so you've got to pull the boat. I'm jealous of guys who don't have to do that.
 
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Impeller changes may be one of the few maintenance items easier in an inboard than an outboard. My old sterndrive with a Bravo3 was ok once you were able to contort into the engine compartment. The Malibu is super easy.

The Verado I have to drain engine oil. Remove prop. Drain lower unit fluid. Remove lower unit. Replace impeller and then reverse the process while paying attention to the shift cable to make sure it’s in the same position as when removed.

I’d much rather do it on the Malibu.
 
Marina Bum said:
On outboards yes but in more modern drives and a few classics you can change them without pulling the drives. I think Mercury Bravo 2's and beyond are like that and every OMC since Cobra and Volvos old and newer including SX drives can be done in the water too. I have Bravo's on my HB and not only do you have to pull the drives but it drops its fluid so you've got to pull the boat. I'm jealous of guys who don't have to do that.
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Please educate me. I have Bravo drives and they are belt driven on the engine. Easy change on the lake. Did I miss something?
 
Before we get too far down this path, the topic of the thread is "Outboard" engines. If you want to start a discussion about sterndrives and inboards, please feel free to do so in a new thread. Thanks!
 
Bart, gotta say I agree with you on this one (y) , as searches a year from now would/could be more productive in different threads....(y)

Bart....the undisputed leader of the.....WW........Mod-Squad......😋

Now, which wordling will be......'impelled' to start the new thread.....:unsure:
 
We were asked to get back onto Outboards but I'll reply to this direct question. All marine inboards engines have both a pick up pump and then a water pump to circulate water or fluid through the engine block. The pickup pump usually has a soft rubber impeller in it like an outboard has in its water pump. And it occurs to me as I write this as another advantage for outboard engines, only one water pump.
 
Water pump replacement on our Mercury outboards has been a love/hate job. This has to do with reinstallation of the lower unit.

Seems like 50% of the time everything goes smoothly, back together in less than 5 minutes. The other 50% of the time, it fights me tooth and nail, sometimes taking hours…to the point of physical exhaustion…trying to get the $#%& lower unit shaft splines to seat properly.

Once I made the mistake of ‘forcing’ the lower unit on by tightening the nuts. Shaft wasn’t seated properly and ended up punching a hole in the crankcase. That was an expensive repair…

I’ve watched all the YouTube videos, read the factory service manuals. Have yet to find the silver bullet that ensures everything goes back together without a fight.

For those of you with Merc’s, what’s been your experience?
 
Rivergoer, a few thoughts you probably already know…I never move the splines once the lower unit is off…or at least that is my intention. If you shift with the lower unit off, you need to get it back to where it was when the lower unit came off or you will not have one of the directions, ask me how I know..You can also move the splines a fraction. If it’s not lining up again. I usually use vice grips and a rag over the splines. I’m in the same boat, most of the times it’s simple, some times the lower unit goes great until the last inch. Then it is back to the beginning. My Volvo penta IO was definitely 10 times easier than my outboard. I replace mine every two years on my outboard and every time they still look Ike new but it beats small rubber parts going up and in…I’m not a marine mechanic but I just can’t see paying for two + hours work plus parts for something that can take me less than an hour.
 
Rivergoer said:
Water pump replacement on our Mercury outboards has been a love/hate job. This has to do with reinstallation of the lower unit.

Seems like 50% of the time everything goes smoothly, back together in less than 5 minutes. The other 50% of the time, it fights me tooth and nail, sometimes taking hours…to the point of physical exhaustion…trying to get the $#%& lower unit shaft splines to seat properly.

Once I made the mistake of ‘forcing’ the lower unit on by tightening the nuts. Shaft wasn’t seated properly and ended up punching a hole in the crankcase. That was an expensive repair…

I’ve watched all the YouTube videos, read the factory service manuals. Have yet to find the silver bullet that ensures everything goes back together without a fight.

For those of you with Merc’s, what’s been your experience?
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Same, putting it in gear first seems to help
 
Jyboat said:
Please educate me. I have Bravo drives and they are belt driven on the engine. Easy change on the lake. Did I miss something?
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All the bravo series lower units have a belt driven pump mounted on the engine, the alpha series have the impeller mounted in the lower unit like outboards. Open your engine compartment and look, my 1997 bravo 3 engine mounted water pump had a plastic cover. Hopefully they have changed that in the past 25 years, as the guy I sold the boat told me the boat sank at the slip as the plastic cover cracked.
 
Ok I bought a 2 year old outboard that has never been run mercury I usually change my impeller every other year should I go 2 years from the time I run it🤷‍♂️
 
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