# Dropping lower unit, replacing water pump-first timer



## Out4Trout (Sep 9, 2019)

Guys, what’s great community this is. I reached out recently about my 90 2 stroke not peeing and got advice/tips from no less than 2 dz of you-thanks! Another question-when I pull the lower unit, can/should I use the below grease on bolts, prop shaft, etc? Want to get this right. Thanks, Wes


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## MikeCockman (8 mo ago)

I’ve not used grease on the bolts, don’t reckon it’d hurt though. The drive shaft and prop shaft certainly need something though. Usually anti seize or grease, I’ve seen both used.


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## permitchaser (Aug 26, 2013)

That grease looks fine. Next time get marine grease. Good for you doing your own impeller. I’d do mine but my back won’t let me. My 140 foot is just a little heavy


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## mwolaver (Feb 6, 2014)

Yes, grease everything. The grease on the shafts wears away quickly (except for in the spines) but you want grease or anti-seize on the bolts for sure....SS in aluminum. Grease the keyway, the impeller hub and arms, inside of the pump volute, the pump bolts, everything. Yes, most of that will go away, do it anyway. 

Take off your prop and grease all that up too and replace with a fresh cotter pin.


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## Smackdaddy53 (Dec 31, 2012)

I do a lot of lower units and use LubriPlate Assembly Lube on the water pump and Lucas Red N Tacky grease on the prop shaft and a little on the water pump bolt threads. No reason to get silly with it, just a little is sufficient.


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## exit (Aug 22, 2017)

I don't know who makes the Quicksilver grease for Mercury but the Extreme grease is exceptional in my experience as is the 2-4-C.


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## Out4Trout (Sep 9, 2019)

Pulled it and the impeller, to me, looks like it’s in good shape…would y’all still recommend replacing? What do I check next, thermostat?


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## exit (Aug 22, 2017)

Out4Trout, that impeller looks pristine but you have already done the work so I would change it and keep that one as a spare.


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## Out4Trout (Sep 9, 2019)

I guess the fins should be vertical, not swept back? Would this deformation above be enough to not cause motor to pee?


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## Frank Ucci (Jan 20, 2019)

I'd change that green gasket while you're in there.


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## Out4Trout (Sep 9, 2019)

Update, changed out everything and she’s peeing! Thanks everybody


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## Smackdaddy53 (Dec 31, 2012)

Frank Ucci said:


> I'd change that green gasket while you're in there.


That’s part of the rebuild kit


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## The Fin (Sep 28, 2021)

Out4Trout said:


> Pulled it and the impeller, to me, looks like it’s in good shape…would y’all still recommend replacing? What do I check next, thermostat?


I just noticed that you completed the service, good job! It’s going to be easier the next time.The labor is the hardest part, replace the impeller and you’ll at least know how/when that service was done.


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## Frank Ucci (Jan 20, 2019)

Smack, is he planning to use the rebuild kit or is he just considering replacing the impeller?


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## Smackdaddy53 (Dec 31, 2012)

Frank Ucci said:


> Smack, is he planning to use the rebuild kit or is he just considering replacing the impeller?


No idea, he said “replaced everything” so I’m leaning towards a full rebuild kit. The full kit is not much more than just the impeller and if the impeller is compromised the wear plate and cup are most likely grooved as well. I think of it like this- if the wear plate and cup are grooved the impeller is that shape as well. Slapping a new impeller in it will not be as effective as a full kit with a new bottom plate and cup. I always replace it all and if some components are ok they are spares. Some rebuild kits do not include the upper cup in the upper housing...food for thought.


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## Mako 181 (May 1, 2020)

I have done a lot of pumps in my time.
I will not open my tool box unless I am going to do a 100% full pump kit for me or anyone else.


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## Frank Ucci (Jan 20, 2019)

Yea, the real pain is wrestling with the lower unit. Once you've put that much effort into the project, you might as well put in the full kit.


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## Capteasterling (Mar 10, 2021)

I found that sticking a lower unit in a bench vise to be very helpful, a wooden rack can be fabricated with little effort also. The biggest thing on the impellers is memory, they may appear fine but they lose suction power when the fins form to the housing. Therefore, even a motor with very few running hrs will need new water pumps at proper intervals.


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