Air filter - intake? Westerbeke 50

sord · **Posted:** 27 Aug 2012 16:47

I have been trying to solve a bit of a black smoke issue and keep reading that I should look at my air intake. The Westerbke manual seems to refer to a 'breather' and a 'silencer'. The silencer seems to be nothing but a convaluted box and the breather is so impossibly hidden under the heat exchanger that I am sure they do not intend it to breath. So what am I supposed to be looking for the make sure I get enough air to the engine?
Frustrating

Velera · **Joined:** 29 Dec 2006 09:38 **Posts:** 656

There is no air filter on a W50. This is common in marine diesels. My new Yanmar has no filter either. You should not need one as you are not operating in dusty areas, though this should encourage us to keep the engine area clean and free of belt residue and dirt. Your smoke residue and soot could be a number of things. Most often this is a sign of unburned fuel. It could be a number of things: in order of what might be the most likely:
1. Overpitched prop (see other postings on this matter). I believe that the T37 was shipped with a substantially overpitched prop which means the engine can never reach the rpm necessary to fully burn the fuel supplied to match the throttle setting. If you cannot reach full rpm at hull speed of your boat, you should expect black residue and reduced engine life.
2. Dripping injectors--they are not spraying fuel but just dripping it in so it is not burned. These can be checked, but my diesel mechanic friends say they last a long time and do not fail nearly as often as they are replaced by boat owners. You can check this by taking one out when engine is running to see if it is spraying or dripping.
3. Worn valves or rings--if this is the cause you probably have other problems, like hard starting and blue smoke from oil and unburned fuel. If you have check #1 and #2 above, you can have someone do a compression test. Pay for a very experience and old mechanic to do this. It is not that easy in a diesel due to high pressures required and you can get misleading results from a defective test.

There is probably some unburned fuel in the operation of even a properly pitched diesel as fuel and acceleration of the boat are sometimes out of synch. So if you, like me, sometimes honk on the fuel lever, there is going to be some soot in the best of cases, but a regular buildup indicates some other issue.

puffcard · **Posted:** 28 Aug 2012 17:28

Velera has good points, especially the over pitched prop. Black smoke is a sign the diesel is over loaded. It's summer time is your bottom and prop clean and how fast are you trying to run the W50. Most all diesels will put out black smoke running wide open.

sord · **Posted:** 28 Aug 2012 18:15

There really is not that much black smoke (I have had really black smoke when I had to reverse full throttle to avoid an accident) It was more a question as to where is the air intake as it seems to be buried under a lot of cooling pipes, exchanger, etc. Without taking half the engine apart is there any way to clean the air intake? Does the air actually enter the engine through a 1/2 inch pipe coming from the silencer? Does not seem like that will provide much air.

My prop was made for my engine (Kiwi prop) from the engine specs. I generally run at a max speed of 7.3 knots with the engine running at 2700 rpm. the bottom and prop are pretty clean as I haul every winter, have anti-fouling and am in a relatively clean lake (Lake Huron)

Splice

puffcard · **Posted:** 28 Aug 2012 21:00

sord wrote:

There really is not that much black smoke (I have had really black smoke when I had to reverse full throttle to avoid an accident) It was more a question as to where is the air intake as it seems to be buried under a lot of cooling pipes, exchanger, etc. Without taking half the engine apart is there any way to clean the air intake? Does the air actually enter the engine through a 1/2 inch pipe coming from the silencer? Does not seem like that will provide much air.

My prop was made for my engine (Kiwi prop) from the engine specs. I generally run at a max speed of 7.3 knots with the engine running at 2700 rpm. the bottom and prop are pretty clean as I haul every winter, have anti-fouling and am in a relatively clean lake (Lake Huron)

Splice

Take a look at this pic.
Piece 1 is the exhaust manifold and intake manifold combine. The air silencer sits on top of Pc 1, the air goes unrestricted thru the manifold and the exhaust comes back thru the manifold to the exhaust elbow. Both are in separate cambers, but both are running thru the manifold. The little hose Pc 6 is for positive crank case ventilation.

sord · **Posted:** 28 Aug 2012 22:30

Thanks

Ok now I understand. I had thought the air entered the engine via that little hose to the breather but could not see that as viable. What exactly is the breather?

Tartan37.com

Air filter - intake? Westerbeke 50

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