MD2020 Exhaust elbow

[JamesHolland]

I have a back pressure problem which seems to be a partial blockage in the exhaust elbow. I've seen a few threads, unfortunately the pics are now no longer showing up (photobucket). I have tried poking a screw driver down the top hole where the seawater should enter, I would assume that that hole would be the same diameter all the way down into the exhaust flow. Is that the case? can I just run a drill down there? I managed to get a dodgy phone pic but it looks like there is some kind of 'channel' in there. I'm out on a swinging mooring which makes life awkward, I didn't have the right tools to remove the elbow when I was there at the weekend

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[duncan99210]

You'll need to remove the elbow, as the blockage will not be simply in the entrance for the raw water: the inside of the elbow itself will be blocked. You may be lucky and able to remove the accumulated lime scale and free up the port that allows the raw water intimate the elbow but it's possible that you'll find that the elbow is corroded to such an extent that when you try to clean it you'll find it causes a hole through the metal.

 

[PetiteFleur]

On my Perkins Perama(same engine as the VP2020) after I removed the elbow, I managed to poke my screwdriver through the cast iron so had to get a new elbow. It was completely rotton. There was only a 10mm diameter in the centre which explained a lack of power. Incidentally the VP replacement elbow was cheaper than the Perkins, identical apart from the paint.

 

[Jokani]

I do not think you will be able to cure this without removing the elbow.

When I removed mine, and tried scraping some crud off with a screwdriver, and the screwdriver went through the walls in 4 different places.

Glad I removed it, as it was very close to failing on its own.

Looking at yours, I'd be surprised if liek me you end up with no option but replace it. If you do I would go for one of the stainless versions.

 

[Jokani]

I must learn to type quicker!

 

[Neeves]

From memory, questionable, the seawater inlet on the top of the exhaust elbow is not long, or deep. It terminates against an 'insert' or a sleeve inside the inlet. So you will not be able to stick a screwdriver very far (and I would strongly advise against it). Take the elbow off, its simply 4 nuts on 4 studs and then re-assess. You may be able to clean the calcium deposit with acid - but if the elbow has gone too far the acid will find the weak spot and dissolve a hole.

Our elbows lasted about 1,000 hours - but much depends on how much dissolved calcium is in 'your' seawater - and that varies.

I have heard, repeatedly, that a stainless elbow is 'better' for calcium deposition - but they may introduce other issues - simply do not know.

 

[ianfr]

I replaced mine with a stainless one from Keypart https://www.keypart.com/stock/861906ss-r

Simple enough to replace and when I tried to clean the old one it disintegrated.