Diesel outboard

Why would his Runsun outboard be any worse than, say, a Honda or Yamaha as far as "dissolving in seawater". Just curious if you know something about this particular motor that i don't ( which wouldn't take much) Is this just more Chinese bashing or are you talking about outboards in general with this comment ? While most outboards do corrode as you say, with reasonable care they do sterling service and have a reasonable service life. boating would be a whole different world without them.

Steve.

 

I lived in Taiwan for 16 months back in the late 90s and there were millions of motor scooters on the road that were made in either Taiwan or China, i don't believe for a minute that they were all crap, nobody would be able to get to work. When i went there i had all the usual bias about everything made in Taiwan being cheap crap. As part of my job as an engineer for a Taiwanese sporting goods company i got to design and have specialized machinery built locally as well as install a lot of imported German machinery and i have to say i was a lot more impressed with the locally made stuff. My point is they can make very high quality stuff or crap just like here in the US, if we accept or in fact demand by way of pricepoint, junk that's what we will get but if we demand a certain level of quality (as the OP says he is doing) and are willing to pay for quality they can deliver it, so if you receive a crap Chinese product in the west, blame the importer and to a degree, yourself for going for cheap. If you expect Yamaha or Honda quality you should not expect it for significantly less $$.

Steve.

 

I've been involved with the import of Asian items more than anyone on this board and I've said this before-with bigger,more complicated items-it's often hit and miss.
Things have improved by leaps and bounds the last few years however.

It's one thing to have your scooter stop running,or your weedeater blow up-but it's a whole different thing to be out on the ocean with your family and have an unproven engine conk out.
However,if they are cheap enough-just buy 2 and have one as a spare.
Such events make the few grand you may save seem quite insignificant.

As their unit costs for most things are so low,most any company that is serious about expanding their markets will provide (for shipping costs) whatever you want for testing,but only if they think you are serious.

Proof is needed.

I can buy a new chinese 4wd 20-30 hp diesel Yanmar/Kubota clone tractor, for $5k..
http://www.alibaba.com/product-detail/Henan-hot-sale-QLN-304-30hp_1994745234.html

or I can get an actual used Yanmar or Kubota often with attachments out of Japan for less money-and I know it'll last 30 years.
http://www.alibaba.com/product-detail/KUBOTA-Tractor-Farm-Equipment_142864837.html

 

Yeah, you would expect that after 200 years someone invented a unit to measure power...

Joris

 

You dont have that boat designer disease do you where they think a 100hp outboard will do the same job as a 100 diesel?

 

Is the outboard a 2-stroke, 4-stroke or diesel?

 

2 and 4 stroke outboard almost the same result as power at 5000ish rpm
if a diesel outboard made power at 5000rpm then you would get the same result but they dont...

 

Has anyone seen the neander shark diesel outboard. 55 hp 4500 rpm turbo double crankshaft and weighs 155kg.

 

Not in production yet, looking for investors although Selva involved.
There is a market but nobody seems to be able to fill it with a EU compliant diesel, funny that a 2 stroke gas engine can but no diesel outboard has yet?
Maybe the powers that be are forcing road transport emissions for a diesel and thats going to be tough
dodgy graphs on the web site.....
Drawings and not photos....
no boat on boat comparisons....

 

Must be another pie in the sky. Looks the goods though.

 

but what if they did? Then a 50hp@ 5000rpm 2-stroke or 4-stroke would have the same power as a 50hp@ 5000rpm diesel ?
Or fit a 1:2 gearbox on a 50hp@2500rpm diesel to give it the same rpm at the output-shaft?

 

I thought we decided they do have the same power, therefore if that is produced at the same rpm then it will do the same job, but they dont so it cant on a planning hull.

PS what happens to torque when you double the rpm?
now your talking like a boat builder...you need to add "change the prop diameter as well", all things you cant do on an outboard to make it work for a diesel

 

Joris
You are correct, if you have a 50hp AT 5000 rpm diesel and a 50 hp AT 5000 rpm gas engine, they will turn a specific prop the same rpm

If you had a 50hp @2500 rpm diesel and ran it though a 1:2 FRICTIONLESS gearbox, you would get the same performance as the 50hp 5000rpm gas engine

Horsepower to the prop is the basic parameter

 

Still not sure why the engine-rpm matters? The rpm after the transmission is what you make it with the ratio you select and doesn't affect horsepower or torque... (ignoring the typical 5-8% losses, Barry) So how you estimate that you need a diesel twice the hp to replace a 55hp 2-stroke or why hp isn't hp remains the question...

 

next lesson
What rpm does the diesel idle at..and what at max rpm and what is the difference is percentage wise?
and now look at the gas engine, they might both pull a skier but one engine will go a whole lot faster compounded by the fact that the gearbox ratio and prop diameter has been optimized for the gas engine.
Harry has proved all this to himself and anybody that has read the thread or used a diesel outboard.