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28-08-2008, 09:04
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#1
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Registered User
Join Date: May 2006
Location: Hampton Roads, va
Boat: Catalina 387 - Magical Dreamer
Posts: 176
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White smoke when starting to backup
I have a new boat so everything is new to me. I have a Yanmar 3gm 40hp with a 3 blade prop. When I put it into "reverse" I get some white smoke from the exhaust. In forward it is fine. It almost seemed to stall, then I put it in forward and the engine regained power. I put it back in reverse and it started to give off white smoke, then once the boat started backwards, the smoke cleared and it was fine.
Any ideas as to why?
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28-08-2008, 09:08
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#2
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Moderator Emeritus
Join Date: Sep 2007
Location: Eastern Tennessee
Boat: Research vessel for a university, retired now.
Posts: 10,406
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White smoke can indicate a lean burning engine. I don't know if this may indicate trouble or not.
__________________
David
Life begins where land ends.
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28-08-2008, 10:33
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#3
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֍֎֍֎֍֎֍֎֍֎
Join Date: Apr 2006
Posts: 15,136
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Brand new boat, or new to you? How many hours on the engine?
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28-08-2008, 10:44
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#4
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Registered User
Join Date: May 2006
Location: Hampton Roads, va
Boat: Catalina 387 - Magical Dreamer
Posts: 176
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38 hours on engine
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28-08-2008, 10:56
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#5
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֍֎֍֎֍֎֍֎֍֎
Join Date: Apr 2006
Posts: 15,136
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White smoke is usually water vapor, but it can be hard to really judge color. With only 38 hours the engine is not yet broken in, you may be seeing some oil blowing by the rings under load. But I'd ask the dealer to have someone take a look at it, you've paid for the warranty with the boat. Could just be steam from the cooling water in the wet exhaust that you're seeing.
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28-08-2008, 13:09
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#6
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Senior Cruiser
Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
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Most likely steam.
Don't baby the engine. 40hrs is not run in and you can kill it with kindness as Pat like to say.
Never heard of, nor seen a lean engine producing white smoke.
I am a little concerned with the engine almost dying when you place it in gear. Do check you have nothing binding. Won't be easy to check in the water. Remember that the entire force of movement transmits through the shaft through gear box and to the engine mounts. So if the engine is soft mounted, the engine and box will move slightly forward and slightly back. So when the engine/box/shaft is pulled back on, ensure nothing is binding up the shaft. Highly unlikely, but it's a boat and anything can happen on a boat.
Ummm, is it a fixed three blader? it's not a folding prop by any chance is it?
__________________
Wheels
For God so loved the world..........He didn't send a committee.
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28-08-2008, 14:31
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#7
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cruiser
Join Date: Aug 2005
Location: No longer post here
Boat: Catalac Catamaran
Posts: 2,462
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If it looks like this it's steam
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29-08-2008, 05:32
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#8
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cruiser
Join Date: Nov 2004
Posts: 4,525
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I get what Rick posted too... for a couple hours on starting with my 2005 30hp yanmar. BUT... it only happens with one engine - the same engine that loses a few hundred RPMs for a few seconds once or twice during a 10 hour day.
The other "twin" engine?
No problems at all.
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29-08-2008, 05:41
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#9
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cruiser
Join Date: Aug 2005
Location: No longer post here
Boat: Catalac Catamaran
Posts: 2,462
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I just assume it's Florida weather causing condensation in the fuel tanks. What's curious is that the water separators don't catch it before it enters the injectors. On the other hand, run the engines hard for an hour and it reduces considerably. If Pat's around, maybe he can shed some light on this??
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29-08-2008, 06:09
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#10
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cruiser
Join Date: Nov 2004
Posts: 4,525
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Quote:
Originally Posted by rickm505
I just assume it's Florida weather causing condensation in the fuel tanks. What's curious is that the water separators don't catch it before it enters the injectors. On the other hand, run the engines hard for an hour and it reduces considerably. If Pat's around, maybe he can shed some light on this??
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Interesting...
Also, the engine I have these problems with runs a few degrees cooler than the one that operates perfectly.
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29-08-2008, 10:38
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#11
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֍֎֍֎֍֎֍֎֍֎
Join Date: Apr 2006
Posts: 15,136
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Something fairly new and interesting, appears to be a student research project:
White Smoke Emissions in Diesel Engines
Combustion Instability in Diesel Engines
Pointing at white smoke as being the result of "misfires" that could be due to fuel leaking past the injectors, bad injector timing, cold engine, possibly bad fuel spray (injector needs overhaul) or other "misfire" issues relating to timing and fuel getting properly shot into the cylinder.
I'm guessing that if anything about diesel engines still had to be "researched" at this point, white smoke must bedevil more than a couple of pros.
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01-09-2008, 17:06
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#12
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Registered User
Join Date: May 2006
Location: Hampton Roads, va
Boat: Catalina 387 - Magical Dreamer
Posts: 176
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And the verdict is...
Running Lean!
Guess that is what happens when you have air in the line. Finally was able to work on her this weekend. We were going to take her out, so I fired her up to idle for a little bit. Well, she started to smoke white and lose power, so I started pumping the throddle and it died. Tried to crank and nothing. Having read the "too lean" post eariler, I figured I would check the bleader. Cracked it and started pumping, 20 pumps later and it started squirting. Cranked the engine a little with the water inlet turned off and she fired up and I opened the through hull. Ran great all the way back today as we had no wind. 5-7 from north when heading south .
Thanks for the tips, you saved a weekend by giving me a point to guess from.
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01-09-2008, 18:05
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#13
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Eternal Member
Join Date: Aug 2006
Location: North of Baltimore
Boat: Ericson 27 & 18' Herrmann Catboat
Posts: 3,798
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Hunh?
Quote:
Originally Posted by rickm505
I just assume it's Florida weather causing condensation in the fuel tanks. ??
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What? I don't understand?
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01-09-2008, 19:56
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#14
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cruiser
Join Date: Aug 2005
Location: No longer post here
Boat: Catalac Catamaran
Posts: 2,462
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Quote:
Originally Posted by Chief Engineer
What? I don't understand?
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water in my diesel fuel.
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