Obstructed water passages & inner ex. tube carbon

[baytonemus]

I can see that there is some scale that is partially obstructing the water passages above grommets inside the exhaust tube. There is actually more obstruction than the photos show (blue arrows). Tough to get a decent pic up in here.



Are those passages cast as part of the tube itself and can I just try to pick that stuff out of there? I'm hoping to reuse the grommets which appear to be in good shape. I'm replace all of the grommets in the lower unit.

Also, there is a hard, crusty carbon deposit in one section of the inner exhaust tube that's about 1/16-18" thick (red arrow). It looks like it will come off easily enough but should I be concerned about its presence in the first place?

Sorry about all of the questions. Thanks again.

 

[baytonemus]

Re: Obstructed water passages & inner ex. tube carbon

I never got a reply to this post so I went ahead and scraped the carbon out of the inner exhaust tube. I figured I couldn't do too much damage.

I'm hoping to put the lower unit back on this afternoon and test it, but I'm concerned about the water passages up inside the outer exhaust tube. When I look up inside there, should it appear that both water passage ways are partially closed off about 2-3" above the grommets? I've looked up inside my other motor and it's similar to what's in the photo in my earlier post. You can't quite see how both tubes are actually closed a little from both sides, so here's a "graphic presentation"...



Those obstructions feel pretty solid when I poke them with a screwdriver.

Also, should I use any sort of sealant or something like silicone assembly grease when joining water tubes and grommets? Thanks.

 

[baytonemus]

Re: Obstructed water passages & inner ex. tube carbon

Maybe they were designed like that in order to increase pressure???