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MBesant 06-11-2006 09:48 AM

Diesel exhaust- water?
New (to me) boat with Universal M18 diesel. Learned to start it yesterday, but have a question
Enigine holds at 175 degree after 20 min running. But no water escapes through the exhaust. Boat has a hot water tank with engine heat and also a Vetus water lift muffler.
The question: Is this OK? Why no water in the exhaust? Does the water tank need to heat up first before water flows through the exhaust? Or should I check the impeller?
So many questions All so new to me
Thank you
Marty Besant
1987 Newport 30
Buffalo NY

tim_rutherford 06-11-2006 10:14 AM

Check Water
The first thing to check after starting the engine is to ensure there is water coming out of the exhaust. It is not gushing, but rather gurgling and spitting.

If you see not water, shut down and check the impellar.


DeepFrz 06-11-2006 10:19 AM

If you haven't melted the engine after 20 minutes then you probably have a water seperator in the exhaust line . This makes for a quieter boat as the water is directed through a hose to exit below the waterline. Stops all the spashing, gurgling, etc.


duffer1960 06-12-2006 09:40 AM

Is the raw water seacock open? Is your impeller ok? I would check these two ASAP. If this is a new to you boat, and it is the first time in the water this season, the seacock may be closed and/or the impeller removed for winterization. ALso, before you open that seacock, make sure it's hose is clamped on securely.

goagebell 06-12-2006 04:34 PM

we have a 33ft.morgan.
we took it out 6 or 7 times no problem.When we headed out this spring leaving ft.pierce to st.louis cranked the diesel at 21rpm. it overheated
to 200,we pulled it back in to changed the impreller,didnt help,checked the
all the things that are on your replys,fortunately a couple that had lived aboard for years hit the nail on the head,it was the heat-exchanger,they
say to look at the exhaust for your sputtering it did, no symptoms an it was the heat exchanger .Wish us luck waiting for Alberto in carrabell

hellosailor 06-12-2006 05:22 PM

"and it is the first time in the water this season, the seacock may be closed " A tirck to learn from aviation ground crew: They put long red streamers on things (like intake covers) that must be removed before startup.

A good way to make sure the raw water intake is open, is to tie the ignition key to the intake valve handle with a red streamer or yarn. You may spend a few minutes asking yourself "Where'd I leave the damn key?!" but you won't start up with the intake closed.<G>

Cat400 06-12-2006 05:57 PM

If you ran the engine for 20 min with no overheat your impellar is fine assuming your temp gage is accurate. If the impellar had failed you would go to overheat in a matter of minutes. The impellar should be replaced every 100 hours...50 hours if you want to be safe.

camaraderie 06-12-2006 08:19 PM

There's no need to replace an impeller that often...especially if you buy the good ones (Globe - as I recall.) We consistently get hundreds of hours from our impellers. The real enemy of impellers is winter layups and lack of use (and of course...closed thru hulls!). Once a year is plenty of changing for most uses.

Cat400 06-12-2006 09:59 PM

Sorry to disagree Comaraderie. We experienced a failure on a new 2004 Yanmar 40 hp diesel engine after only 34 hours of service. I agree once per year it should be serviced but should not exceed 100 hours to be on the safe side. If you plan on extending be sure to carry a spare and know how to replace it. As you know on some boats it is not so easy especially when you are on anchor.

sailingdog 06-12-2006 10:39 PM

Also, replacing the stock impeller cover with a quick change cover can make impeller changes far easier.

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