First time pulling a riser with questions about condition w pics

[MalibuMike]

First time pulling a riser with questions. As a new boat owner, this is all new territory for me to pull a riser and assess if it is usable or not. Attached are some pictures that show some clogging in the passageways but most of it is easily removed with a flat blade screwdriver. The walls seem very thick and it does not appear to have any danger of water penetrating a wall and going down the throat of the exhaust to the manifold. Are these serviceable?In other words, do people sometimes just chip away at some of the gunk and put a new gasket on them and reuse them?

 

[alldodge]

Look ok to me, clean up and reuse

 

[cptbill]

Got some questions. How long have they been on the boat, is this the first time they've been taken apart, was there a metal gasket on there and why are you taking it apart is there an issue?

 

[MalibuMike]

There was a small seepage rust spot forming at the gasket between the riser and the manifold. When the boat was last in for outdrive service the mechanic said it might be time for riser gaskets. There’s a really cool shop in Oxnard called Base auto and Marine. The guy working at the shop seems to be extremely knowledgeable about all things boat related and I brought the manifolds and risers into him and he believed they were perfectly serviceable. He sold me some sort of redline solution to soak them in that will help get rid of the rust and clean them up. He said I could get some sort of tech tool and just kind of clean up all around the edges. The wall thickness is were looking very good. He said the redline was better than the barnacle buster solution. I’ll post some more pictures soon as I have other questions about how to clean The round cylinder that runs along the entire bottom of the exhaust manifold. So far it was very easy taking all the bolts off and all the surfaces look very easy to clean. He also suggested painting the risers and manifolds as it makes it easier to look for leaks or rust streaks. I was truthfully nervous about I’m doing all the bolts but it looked like the previous person use some anti-seize compound and it made it fairly easy to take them off. This is a new boat to me and even with a history of receipts going back to 2017 I do not see any service for manifolds or risers. The boat only has 650 hours on the motor and was hardly used by the previous owners.

 

[MalibuMike]

Well so far this has been not too bad! The product is called rydlyme . I scraped off as much interior stuff as I could and the passageways are really opening up now. The brass plugs on each end were so full of sediment that you could not see through the hole. A bunch of black sludge was in there. Should I run some sort of shotgun cleaning bristle through this area? Also, you can see that there is a crack in the round portion of the riser. The rubber boot doesn’t really even grip onto this place so I’m wondering if this is not really a big issue. Also there are some brass plugs threaded into the sides of the risers. They have some kind of orange plumbing putty around the threads. It is not Teflon tape but it’s some thing that looks like it was painted on before screwing in. Anyone know the name of the stuff?All the pictures are before I stuck them in the bath to clean. I will show finished images once I’m done cleaning. One last thing, The surfaces where the exhaust manifold gaskets will be going are very flat and will clean up very easily. There is a very slight raised rusty edge next to it where the gaskets did not touch. I can scrape down most of this down. Should I use Emory sanding paper with a flat sanding block to knock the lip down?

 

[alldodge]

Your second pix is the only one which makes me take a second look

Take a wire wheel to things and see how it turns out

 

[Lou C]

Hello ok I don’t like that crack on the outlet of the elbow. I’d at least replace the elbows since they usually rot out faster. I’d think about getting the sealing surfaces of the manifolds re surfaced at a machine shop if they look good otherwise.

 

[MalibuMike]

Well the first quote from a machine shop was $150 to throw them on some sort of belt sander. I already have one brand new riser that came with the boat so I could probably buy another brand new one for under 200. If the manifolds look good, would it be foolish to throw new risers on top of used manifolds?

 

[dwco5051]

That orange (red) on the brass plus is more than likely just pipe dope. Could be Permatex, Locktite or any other brand of pipe sealer. I think the companies made it red so us old timers would think it was as good as the old red lead pipe dope.

 

[Lou C]

Well the first quote from a machine shop was $150 to throw them on some sort of belt sander. I already have one brand new riser that came with the boat so I could probably buy another brand new one for under 200. If the manifolds look good, would it be foolish to throw new risers on top of used manifolds?

Not really as long as the sealing surfaces clean up well. I might check for leaks by filling with acetone (careful flammable), acetone will find leaks that water won’t.
Here in the salt pond it’s fairly common that people will put new elbows on the old manifolds and then change both during the next change; IF they pass the acetone test.

 

[MalibuMike]

OK so just to make sure I have the straight. Put the brass plugs on the bottom of the manifold to seal up any place for the acetone to go. Pour through the water jacket slots on top and fill it to the top then checking to see if anything is running through the exhaust ports?

 

[Lou C]

What I do is prop it up level, pour it in via the feed hose till it reaches nearly the top of the manifold and watch the level, see if it drops & watch the exhaust ports.

 

[Scott Danforth]

according to this pic. you need to replace them.

 

[jerryjerry05]

#2 pic says you need risers.
The clog is in an area that isn't readily
visible, the crack shows failure and it won't be long
before it goes through and back into a cylinder or 2

 

[Lou C]

What I said, don’t like that crack in the outlet of the elbow that suggests significant rust. See how they can look good on the outside but problems are lurking within...

 

[Lou C]

That orange (red) on the brass plus is more than likely just pipe dope. Could be Permatex, Locktite or any other brand of pipe sealer. I think the companies made it red so us old timers would think it was as good as the old red lead pipe dope.

You can use OMC gasket sealer or Permatex Aviation when you put those back in, just to make it easier to remove them when you do replace the manifolds eventually. Those elbows that the hoses connect to, save em because VP probably charges $15 each for them! They are actually OMC spec parts. The drain plugs same thing, just coat with OMC gasket sealer or similar. I've been doing this for years and never had a drain plug seize up even in 100% salt water use.

 

[Bt Doctur]

this area looks suspect
click to enlarge

 

[cptbill]

If it were me I think I'd put new manifolds and risers on it and be done with it

 

[MalibuMike]

So the acid bath did eat a lot of stuff and I pulled the brass plugs and forced out a lot of gunk in that lower round cylinder chamber. I am now sending the surfaces and one in opinion of just how perfect they need to be since the gaskets are kind of thick and look like compress a little bit. I took a metal file to knock down some of the crusty edges that raised up that were outside of the gasket area. I’m now using a flat block with some emery paper to make sure the surface is smooth. There are still some very minor imperfections and I just don’t know how perfect these need to be on the exhaust ports. The top of the exhaust manifold is very clean and flat. I’m not too worried about the riser attaching to the manifold.

 

[jerryjerry05]

Buy the Volvo parts if you got $$ 450-500 each.
Osco is a US company 179$ one manifold.
They sell parts here but no manifolds.