Impeller Replacement Issues

So.... I decided this weekend to change out the impeller on my 1994 Mercury 25 HP motor. First I couldn't get the lower unit to drop but thanks to the magic of youtube I learned about pulling the starter to get to the shift linkage.
Now with the lower unit down I proceed to get down to business. The first thing I discover is that there are two gaskets for the gear housing to face plate, one a little thicker than the other. I search on the web and can't figure out which one or both to use. It looked like there was only one on there when I took it apart so I used the thicker of the two.
I put one of the two plastic washers down the shaft. Then I replaced the little keyway thing on the shaft and slid the impeller down. Next I slide the other plastic washer onto the top of the impeller.
I put the new O ring on the housing and slid that down the shaft while stuffing the impeller in the housing while spinning it clock wise.
I put everything back together and the shaft is hard to turn by hand but I don't know if this is normal. I put the lower unit back on and start it up and there is a very small amount of water coming out and then none. I shut it down. I took the boat back to the storage lot and drove home depressed and defeated.

What went wrong? Any help would be greatly appreciated.

One thing to make sure of on reassembly is that the rubber/plastic tube on top of the water pump housing is properly mated with the tube inside the main housing. If upon reassembly those tubes aren't aligned with each other you won't be getting any water to the powerhead.

I will check that out when I break it apart again. That is one thing I didn't even consider. Thanks.

Take it to a ramp and back it down far enough to submerge the pump. Try it there before tearing it apart again.
Sometimes a cheap pair of earmuffs will do what you describe. The ones with the plastic arms are the worst.
You may have damaged your brand new impeller by this point but I would try this before doing it twice.

Pappy said:

Take it to a ramp and back it down far enough to submerge the pump. Try it there before tearing it apart again.
Sometimes a cheap pair of earmuffs will do what you describe. The ones with the plastic arms are the worst.
You may have damaged your brand new impeller by this point but I would try this before doing it twice.

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It was pumping water before I replaced the impeller and I've run it on those muffs plenty of times. The muffs have metal arms.
It might be worth taking it apart again just to see if I damaged anything.

What are your thoughts on the 2 gasket thing I mentioned? Was I supposed to stack them or just use one? How would I determine which one to use?

I was wondering if you pulled it apart again and what you found? I will be doing this in a few months, so have kind of focused in on any thread having to do with swapping out the impeller.

LDUBS said:

I was wondering if you pulled it apart again and what you found? I will be doing this in a few months, so have kind of focused in on any thread having to do with swapping out the impeller.

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I am about to go out now and give it a go. Waiting for my wife to get up so I can make breakfast and get to work. The beauty is that the weather is nice enough to do the work in my driveway. I had to take it to my warehouse before and it's kind of a pain in the backside.
I will post back when I get her running.
I also have to figure out why the reverse lock is always engaged. Even in forward gear. I'm sure that's going to be an adjustment, a missing part, or lubrication.

Update: Took apart everything and then slapped it back together. I'm quite sure I had it right but didn't wait long enough for the thermostat to open. It's probably a good thing I didn't. Turns out I wasn't paying attention when I mixed my gas/oil. Seems I mixed for 5 liters instead of 5 gallons. I happened to notice the bottle when cleaning out my truck. More oil mixed in and motor starts up and runs good and is peeing like a champ!

The good news is that everything I do on this motor gives me that much more experience. This is my first outboard so everything I can learn is a big help.

Thanks for sharing. Big help to people like me too.