Merc 888 exhaust risor elbows?

[Boomyal]

At the exhaust end of the 888 risors, both on the right side, there is a drain plug. Why is this here? I'm not even sure that the manual specifies to pull these plugs for winterization, but I did pull them. At first, no water came out. I stuck my pocket screwdriver into the holes, could feel a lot of grit, the got a signifigant burst of water once I cleared the grit.

Without having one of these in hand, I can't see how or why it traps water and crud. It seems that they trap enough water to do freeze damage even if the manifolds themselves are drained. I'm wondering if this might have anything to do with the breach in my risor boot.

 

[Don S]

Re: Merc 888 exhaust risor elbows?

If the water passages in the risers are partially plugged up, then you may have hot spots of exhaust with no water. That will burn holes in exhaust hoses.

 

[Haut Medoc]

Re: Merc 888 exhaust risor elbows?

Exactly what Don said...If the risers get clogged it will fry the boot....
However, I think that it most likely had a totally clogged riser & fried the rubber at least once before....
They are rather hardy & only really cook once you have an total absence of water....
Curious, is this a closed or raw system?
I have seen alot of 888's , but the one I have is the one of very few FWC rigs that I ever see someone post about.......
Fredwarner1 on ebay sells those risers for about 75 bucks apiece ......
New......
Well worth it......JK

 

[Boomyal]

Re: Merc 888 exhaust risor elbows?

It's a raw system Haut. I am familiar with the construction of the elbows on my OMC and they do not have such drain plugs as the Merc elbow. This is why I cannot picture the flow and where the plugs fit in. I will check with fred warner.

Here is a picture of my style of risor. You can see the little silvery plug heads at the lower right of the exhaust side.

The cavities? behind the plugs were plugged up with sandy looking grit. Do you think that would have impeded water flow and is it possible that once the grit is gone the risors are salvageable?

 

[Haut Medoc]

Re: Merc 888 exhaust risor elbows?

They are just drains at the dead end to prevent possible freeze damage, grit will settle there naturally.....
You could clean them out, but I doubt it will help.....
I would be more inclined to believe that scale from the manifolds & risers built up in the dump holes & partially restricted flow.....
Like I said, this set might be OK, & the bulk of the damage may have been done by a prior blockage.....
You could pull the large plugs & rod them out & see how much scale you can dislodge....
If it is alot, just remember that if a manifold or riser fails, it will put water directly into your cylinders.....
That scale was once part of the riser.....
Or part of the manifold, or block if it was run in salt....
It is up to you to evaluate the their true condition.....
Did they appear clogged at all at removal?
Other than the cost, I don't see why they don't make them out of brass or stainlesss, they would last a lifetime............JK

 

[Boomyal]

Re: Merc 888 exhaust risor elbows?

I haven't pulled them yet Haut. The cute little BeachCraft is buttoned up, outside, for the winter. At least I have a Costco Canvas Carport for my GulfStream. Oh how I would love to have unlimited indoor space. Why life could go on 24/7/365 instead of us getting fat between now and May.

Had to laugh at the weather news this morning. They said we were going into a rainy spell that would last into next week. I told Mrs Boomyal that they really should have told the truth and said 'until next May'.

ps, yes I am aware of rust. Steel expands 17 times when it rusts. You clean off signifigant scale and you may not have any meat left.

 

[Haut Medoc]

Re: Merc 888 exhaust risor elbows?

Pouring here too, but they reopened Dungeness season, so I'm gonna leave it in until December....
Hopefully, I will get a couple days of reasonable weather!
One of the benefits of a closed system is that you really don't have to winterize.....
I start 'er up on the muffs once a week or so .....
& take 'er out on those rare days in winter where you got a 60 degree day.....JK

 

[Boomyal]

Re: Merc 888 exhaust risor elbows?

I was hoping to get out in November. For the last 6 years I did an mid-October camp/crab trip with the Boy Scouts. We invariably had good weather during the day and oftened poured like, well like the PNW, at night. The only problem with October was the crab shells were still soft and pretty skimpy on the meat.

Now I'm done with Boy Scouts so was hoping to do a later trip for better crab with worse weather. We've crabbed at Tillamook Bay with good results. I'don't mind getting wet or cold during the day but I would hate to have to go back and camp so with an adult only trip we'd probably do one nite in a local motel.

With my Gulfstream and it's log style mani's only my engine is on the closed system. That's still better than raw. Not only do I protect the engine I get to run a 180 deg stat. My motor likes that much better.

I don't do much in salt water with my boat but I'm thinking about getting some saltaway, even if just for the mani's.

 

[Boomyal]

Re: Merc 888 exhaust risor elbows?

....take 'er out on those rare days in winter where you got a 60 degree day.....JK

You mean like next March?:%