Exhaust leak from lower unit?

[HiTekRedNek]

Hi all, I just bought an 04 Sea Ray 180 with 3.0L engine. I'm a newbie to boating and marine drive units, but a pretty accomplished land-vehicle mechanic. So I hope to be a quick study.

The boat ran great when I test drove it. It sounded "normal". My concern is some light gray residue on the outside of the lower unit. It looks like a residue you'd see near an exhaust leak on a land-vehicle. I didn't notice this before the test run. Maybe it was there, maybe not. My understanding is that the 3.0L exhausts solely through the prop. Is it normal to have this type of residue high up on the outside of the lower unit? It's on the outer surface of the paint/powdercoat so I don't think it's corrosion. I'm in Northern Wisconsin, far from any salt water so I doubt it's salt (plus, yes, I licked my finger rubbed it in the gunk and tasted it... no it doesn't taste like salt )

Is this something I should run to ground before operating the boat? If so, can you offer any troubleshooting tips? Thanks!

 

[Bondo]

Ayuh,..... Welcome Aboard,..... The grey film is dried minerals from the water, probably lime, like I always got in Lake Ontario,.....

Just so ya know, there are idle relief ports in the transom housing just down inside where yer finger is too.....
Only when runnin' along in gear does all the exhaust exit through the prop,.....

 

[HiTekRedNek]

Ayuh,..... Welcome Aboard,..... The grey film is dried minerals from the water, probably lime, like I always got in Lake Ontario,.....

Just so ya know, there are idle relief ports in the transom housing just down inside where yer finger is too.....
Only when runnin' along in gear does all the exhaust exit through the prop,.....

Bondo, thanks for the reply and the welcome! The idle relief ports you mentioned... are they there because there's too much back pressure funneling exhaust down to the prop at idle? Trying to figure out as much about this beastie as I can. So plz pardon my exuberance! I do appreciate the info.

 

[flashback]

Get a hold of a oem manual so you can get familiar with what you're dealing with. Depending on previous maintenance you could be in need of some new parts. Prevention is a good thing.

 

[HiTekRedNek]

Get a hold of a oem manual so you can get familiar with what you're dealing with. Depending on previous maintenance you could be in need of some new parts. Prevention is a good thing.

Thanks! I'm scouring the web for anything technical from Sea Ray, Mercruiser, and Shoreland'r that I can get my grubby hands on! This boat is 19 years old with only 250 hrs on the clock. That's an average of about 13 hrs per year. So I'm guessing the age gremlins will get me before the wear and tear gremlins. I don't have the service history, but I'd bet it's not been totally up to speed.

 

[flashback]

The mercrusier manual #14 is for the alpha 1 gen 2 which is probably what you have. It covers the outdrive. There's a lot of rubber bits that go bad over time..

 

[HiTekRedNek]

The mercrusier manual #14 is for the alpha 1 gen 2 which is probably what you have. It covers the outdrive. There's a lot of rubber bits that go bad over time..

Thanks!

 

[Scott06]

Bondo, thanks for the reply and the welcome! The idle relief ports you mentioned... are they there because there's too much back pressure funneling exhaust down to the prop at idle? Trying to figure out as much about this beastie as I can. So plz pardon my exuberance! I do appreciate the info.

As mentioned minerals from water get baked on as outdrive gets hot when running especially this part that is not under water on plane

Completely normal use clr to remove if you care to. Any product that made to take mineral deposits off bathroom fixtures will work

 

[nola mike]

The idle relief ports you mentioned... are they there because there's too much back pressure funneling exhaust down to the prop at idle?

Yes

 

[HiTekRedNek]

The mercrusier manual #14 is for the alpha 1 gen 2 which is probably what you have. It covers the outdrive. There's a lot of rubber bits that go bad over time..

Flashback, I found a pdf copy of Manual #14 online. 673 pages of technical enlightenment! Great suggestion! Thanks again.

 

[HiTekRedNek]

As mentioned minerals from water get baked on as outdrive gets hot when running especially this part that is not under water on plane

Completely normal use clr to remove if you care to. Any product that made to take mineral deposits off bathroom fixtures will work

Thanks for the tip. I took a bit of white cleaning vinegar diluted on a wet paper towel to it. Comes right off with minimal elbow grease!