Engine burn out

vega1860 · Mar 29, 2014

A diesel engine under heavy load emits black smoke. I think Douglas is saying that the prop size and pitch should be matched to the engine and transmission gearing for best performance and engine life. Merely installing a bigger or more aggressively pitched prop would be counterproductive and could damage the engine."Fair winds",Chuck RoseSV Lealea, V1860at Petersburg, Alaska

groundhogyh · Mar 29, 2014

Think of it like ur 10 speed bike. In a boat u only get to choose one gear setting or speed. This is the gear that makes the engine most happy. And the engine then produces max horsepower for you and puts this horsepower into the water behind u. If u pick the wrong prop, it might be like u on ur bike always having to use speed 10. Or always in speed 1. Although these gears are handy sometimes, on a flat away, you can probably Put most power into the wheels at like gear 4 or so. groundhogSent from my iPad

tiempo2010 · Mar 29, 2014

When a prop of the correct diameter and pitch is used the engine will be able to achieve its maximum rated rpm. If you can rev higher than this the you are under-propped. The prop has either not enough pitch or diameter or both. If you cannot achieve rated maximum rpm you are over-propped and pitch or diameter or both need to be reduced.

lewills30 · Mar 29, 2014

Hi all,So how do you find this magical fit? Will the prop supplier have the know how to match a prop to the max. rpm? What are some of the choices for the Vega ? Is the folding prop a good bet? Two blades or three? I too am lost on this one. thanks,larrySent from Windows MailFrom: Brian StannardSent: ?Saturday?, ?March? ?29?, ?2014 ?7?:?17? ?PMTo: AlbinVega@yahoogroups.com

When a prop of the correct diameter and pitch is used the engine will be able to achieve its maximum rated rpm. If you can rev higher than this the you are under-propped. The prop has either not enough pitch or diameter or both. If you cannot achieve rated maximum rpm you are over-propped and pitch or diameter or both need to be reduced.

SVFlyAway · Mar 29, 2014

SteveB has it worked out for the Beta 14. But I'd like to recommend a book for the technically inclined (but lay folks like me). There's a ton of good information in the book. It is easy and actually fun to read as he is an entertaining and "patient" author.
"The Nature of Boats" by Dave Gerr. Amazon has it. Dave is a Nautical Architect from New York ( as I recall) and the book is full of information on boat design and function; and why things work as they do. I've read my copy so many times the cover is nearly worn out.

He also has another book "The Propeller Handbook" that is specific to the prop. While he has a lot of information on props in the "Nature" book, this one really delves into that one topic. (This Propeller book is a little more on the technical side than the "Nature" book though). Amazon says they are out of this one 'temporarily', but it is available from some of the used book sellers they list.

tiempo2010 · Mar 29, 2014

A good prop manufacturer or prop shop does - it is their job just like the tailor makes the suit fit. Here is one example, West by North who make the Campbell Sailor prop as well as sell the Autostream, Slipstream, Kiwi props as well as others. Here is their propeller recommendation form http://www.westbynorth.com/PropRecommendation.aspx
In addition to this information with a production boat there is a good chance they have fitted props to others with the design in the past.

pjacobs55 · Mar 29, 2014

I agree ... it's a fine line. Most reputable prop makers can gauge the pitch and diameter you need if you fill out their questionaire. My personal prop favorite is the 3-blade Campbell Sailer made locally. They are sold by West By North . At the top of their home page is a Propeller Recommendation Form link. This form will give you a good idea of the information you need to submit to a prop maker in order to pick the right prop.Also, if your prop is not quite right, but close to it, they can re-pitch it to have either a bit more or a bit less thrust.Peterwww.mostlyaboutboats.ca

tomfentonvega2977beowulf · Mar 30, 2014

Thanks, everyone. I've got it now. (Hadn't heard a prop called a wheel.) The David Gerr book sounds good. I will use the West by North form if/when I change the engine. A great thing about this group is the archive is a collective memory. In my case invaluable.

groundhogyh · Mar 30, 2014

I had a weird transmission ratio on my MD6A as previous owner somehow changed to a fwd/rev transmission, but retained the 1.41:1 (?) transmission ratio. I purchased the feathering Max Prop. With this you can adjust the pitch when you have the boat up. When my motor blew (probably due to years of over prop) i simply readjusted to the new motor. It was a good investment for me as the michigan wheels were like $600 (?).gh

n4lbl · Mar 30, 2014

My MD6-a has a "normal" (forward/reverse, not combi) and IIRC the reduction was 1.91. While I obviously couldn't measure to hundredths I counted prop turns while hand cranking.

pelagicasd · Mar 30, 2014

Lyric had a serious problem with soot on the transom. We found that the mixing elbow on the Yanmar was encrusted with what I presume was salt. Very little water was getting through. Muratic acid (acido muratico in mexico where we were at the time) cleaned it out. The smoking problem changed from black to light gray. The transom has been clean since. Be very careful, a friend tried to clean aluminum cleats and they dissolved. You can imagine what it could do to you if used incorrectly. Walt To: AlbinVega@yahoogroups.comFrom: alan.schulman@...Date: Sun, 30 Mar 2014 13:59:22 -0600Subject: Re: [AlbinVega] Re: Engine burn out

My MD6-a has a "normal" (forward/reverse, not combi) and IIRC the reduction was 1.91. While I obviously couldn't measure to hundredths I counted prop turns while hand cranking.

tomfentonvega2977beowulf · Mar 30, 2014

What is a "mixing elbow"? Is this about maintaining the water cooling channels in the engine? How is that done? I also get each year a build up of black soot on the transome around the exhaust outlet. It comes off okay with ordinary domestic cream cleaner. Does it indicate something's amiss?

9558345ad3d32553d67b49254fbbb61d · Apr 1, 2014

Tom, Group,I am a little perplexed about this business of "soot" and "engine burnout". I spent a number of years in the development and testing of diesel engine fuel injection systems and black smoke/soot is a sign of overload such as would occur if the engine is over-propped. In the case of the engines that I worked on - between 40 and 2000hp. the maximum fuel stop would be set up that there would be little/no smoke in the exhaust, indeed the obscuration of the exhaust was a way of measuring the fuelling level.
Many diesels would have an excess fuel control which allowed excess fuelling whilst starting, including some small craft Volvo engines, but normally fuelling would be limited below the level of noticeable black smoke, indeed, if road vehicles emitted such levels of smoke/soot, the driver would be prosecuted under the Construction and Use Regulations. However, I have never known reasonable "over-fuelling" to cause damage to an engine and in some uses engines are deliberately over-fuelled under certain conditions.
Of course, there is cause and effect, a engine or exhaust system requiring de-coking can cause black smoke as will a partial blockage in the air intake side but other colours of smoke indicate different problems.
I have not studied the fuel injection system on the small Beta Diesels to see if they have a "proper" fuel injection system, but I know that certain small engines have very simple injection pumps.
Geoff#################################################Geoff Blake, G8GNZ JO01fq: Chelmsford, Essex, UKgeoff@... or melecerties@...
Using Linux: Ubuntu 11.04 on Intel or Debian on UltraSparcand Apple OS X 10.8.2 Mountain Lion on my Macbook Pro. Avoiding Micro$oft like the plague.#################################################

pelagicasd · Apr 2, 2014

Tom, I'm no expert and Geoff certainly knows more then I do. My understanding is that the mixing elbow is where the exhaust gases and cooling water mix before they enter the exhaust discharge hose. The elbow is on the rear of the heat exchanger (on my Yanmar). If this was restricted would it cause the engine to overload? Geoff, your thoughts? Walt To: AlbinVega@yahoogroups.comFrom: geoff@...Date: Tue, 1 Apr 2014 16:56:52 +0100Subject: Re: [AlbinVega] Re: Engine burn out

Tom, Group,I am a little perplexed about this business of "soot" and "engine burnout". I spent a number of years in the development and testing of diesel engine fuel injection systems and black smoke/soot is a sign of overload such as would occur if the engine is over-propped. In the case of the engines that I worked on - between 40 and 2000hp. the maximum fuel stop would be set up that there would be little/no smoke in the exhaust, indeed the obscuration of the exhaust was a way of measuring the fuelling level.
Many diesels would have an excess fuel control which allowed excess fuelling whilst starting, including some small craft Volvo engines, but normally fuelling would be limited below the level of noticeable black smoke, indeed, if road vehicles emitted such levels of smoke/soot, the driver would be prosecuted under the Construction and Use Regulations. However, I have never known reasonable "over-fuelling" to cause damage to an engine and in some uses engines are deliberately over-fuelled under certain conditions.
Of course, there is cause and effect, a engine or exhaust system requiring de-coking can cause black smoke as will a partial blockage in the air intake side but other colours of smoke indicate different problems.
I have not studied the fuel injection system on the small Beta Diesels to see if they have a "proper" fuel injection system, but I know that certain small engines have very simple injection pumps.
Geoff#################################################Geoff Blake, G8GNZ JO01fq: Chelmsford, Essex, UKgeoff@... or melecerties@...
Using Linux: Ubuntu 11.04 on Intel or Debian on UltraSparcand Apple OS X 10.8.2 Mountain Lion on my Macbook Pro. Avoiding Micro$oft like the plague.#################################################

tiempo2010 · Apr 2, 2014

That's right Walt. It clogs with crud and I have seen then restricted to 1/4 ".

9558345ad3d32553d67b49254fbbb61d · Apr 2, 2014

Walt, Brian, Group,Hey, take it easy, I am no expert!Diesels produce black smoke when it is over-fuelled (there is too much fuel for the available oxygen) and the unburnt part of the fuel is converted to soot (the burning is not a simple reaction) and produces black smoke. Any reduction of airflow that may be caused by a blocked air-filter to a partially blocked exhaust will cause an over-fuelling situation and probably excess smoke. It has always struck me that the typical water-injection elbow was a rather inelegant solution causing a too rapid cooling of the exhaust gases.
A rule of thumb that test bed engineers used is that the back pressure in a diesel exhaust system should be minimised for maximum power whereas petrol engines the back pressure may have to be "tuned" for best performance.
Geoff#################################################Geoff Blake, G8GNZ JO01fq: Chelmsford, Essex, UKgeoff@... or melecerties@...
Using Linux: Ubuntu 11.04 on Intel or Debian on UltraSparcand Apple OS X 10.8.2 Mountain Lion on my Macbook Pro. Avoiding Micro$oft like the plague.#################################################

tiempo2010 · Apr 2, 2014

Diesels are relatively simple. They need 3 conditions to function properly. Clean fuel, compression, and lots of air - both in and out. Exhaust elbows are a common failure point. I believe Yanmar says to replace every 5 years. One symptom of a clogged elbow, besides soot from the exhaust, is an engine that revs fine in neutral but not under load.

9558345ad3d32553d67b49254fbbb61d · Apr 3, 2014

Group,Just to emphasize what Brian said, diesels are simple, all it needs is fuel and compression to work. Compression means sufficient airflow and being cranked fast enough. Fast enough doesn't mean very fast, it is easy to hand crank a diesel with a decompressor (and a good flywheel). Unlike a petrol engine, a diesel only has to be turned through one compression to start. I have seen a big (130hp) Gardners Engines started by hand on a number of occasions.
Geoff #################################################Geoff Blake, G8GNZ JO01fq: Chelmsford, Essex, UKgeoff@... or melecerties@...
Using Linux: Ubuntu 11.04 on Intel or Debian on UltraSparcand Apple OS X 10.8.2 Mountain Lion on my Macbook Pro. Avoiding Micro$oft like the plague.#################################################

dougpol1 · Apr 4, 2014

The only thing I would add to that that if the boat is tied in the
slip where it can't move through the water it probably won't come up
to speed but if it is driving her through the water there is less
resistance or load on the wheel and she should come up to RPMs. With
out a doubt you know this Brian. But some may not. Been down
working on Sea legs since last Friday. Also did not painted her
bottom last summer but scrubed her a in June. Later in the fall I
scrpped her and scrubbed her again using my little air compressor
and wet suit. I checked her over the weekend and she had 9 barnicels
on her. I have always heard that barnicle strick i9n the spring and
summer and the grow all winter. I claned her late on the premis and
it seems to have worked well. He botttom looks good so I may scrub
her
his si ummer as well and then pauint her bottom in the fall. I am
hoping to be able to go South next winter and it would be nice to
have a fresh bottom. We are panning a couple hundred miles of
sailng the first few works in June as a getaway as well.
--
Doug Pollard
Albin Vega Sea Legs 2225
KK4YGO

On 04/02/2014 07:55 PM, Brian Stannard
wrote: