Suzuki DT-8 Water pump question

[KOTARA]

I've just opened up a recently purchased Suzuki DT8 (1989 model) to replace the water pump impeller. Under the pump plate there was a lot of hardened salt crystals that I've scraped out. There's also a channel that lines up with a small hole in the plate. This was clogged up too.
I'm not sure what this channel and small hole in the plate are for.
Can anyone let me know? Also where I've cleaned out the salt it's exposed bare corroded metal. Would I be best to paint it or protect it with something, to try and prevent further salt build up and corrosion?
A bit of a Kiwi winter project for me.
Any info much appreciated

[Oldman2]

Seems like your post got missed by the usual suspects for water pump questions so I will jump in and say in my opinion the small hole and groove is to drain the water pump and feed tube once removed from the water. Stops the tube etc sitting with too much salty water inside if not flushed after use.
You have to love the Russian repair centers, this video has them "adapting" another make pump to a DT8 with a worn and no longer available pump housing.

https://www.youtube.com/watch?v=a0syUQFZEnQ

[KOTARA]

Thanks for the info and video Oldman2!
Looks like that Russian guy knows how to make the most of old bits and pieces! Got the odd word like Suzuki, poomp and corrosion ! A great video of how to get round a problem.
I think you’re right about that being a drain hole and channel, I was thinking that it may be to prime the pump, but your idea makes more sense.
Does anyone have any suggestions on what paint or product to use on the exposed metal after removing the corrosion? Thanks again

[Oldman2]

Click the right buttons at the bottom of the video and you get English subtitles.

[KOTARA]

Thanks again OM2. I'll cancel those Russian lessons I booked!
Another question for you or anyone else.... I see on the video that they used sealant/ gasket goo under the original pump plate instead of a gasket that would normally be fitted there.. maybe because they altered the original plate or didn't want to add more height to the pump body.
Some videos I've see - people use a gasket and additionally put sealant on the mating surfaces too. Is this needed or is the gasket alone sufficient to make a seal?
If using sealat. What is the best brand, type to use?

[paintman]

Interesting video.

Gasket sealant gives a belt & braces seal when used in conjunction with a gasket esp when the mating surfaces have slight damage such as light pitting or light scratches. Not all gaskets should have a sealant & that usually includes head gaskets.

Best guided by the factory workshop manual as to what should be used & where.
Some engines don't use a gasket but an instant gasket/adhesive, esp on oil sumps.
You will occasionally find paper gaskets where the spec is to use grease as the sealant.

I've used a lot of different sealants over the years - esp in the 70s trying to make old British motorbikes oil tight - but my go-to for a very long time on gaskets & some metal-to-metal mating surfaces has been Blue Hylomar.

Don't be tempted to slather sealant on joints as excess will be squeezed out & may break off & finish up in parts of the engine where it shouldn't be & cause blockages. This is a particular issue with the RTV 'Instant gasket' type which is often used instead of a gasket - even where a gasket is specified - & in bad cases can look like an attack of 'silly string' which is not what you need in oil or coolant passageways.

I'm sure others will have favourites

[KOTARA]

Thanks Paintman
I've used hylomar before on motorbikes, works well. I don't have a manual for this outboard so don't know what Suzuki recommend at at the water pump, just saw the part number for liquid gasket on the parts list I downloaded (no longer available, I guess due cancerous danger).
I haven't had much experience with outboards but guess similar to other engines but harsher conditions especially in salt water.
I guess so long as it pumps well all is good, I'll test it out with a drill in a water tank like on the video.
Cheers