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Old 11 October 2008, 15:27   #1
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High Altitude Sib/Engine Fishing

We are planning a trout fishing outting using a 3.20 mtr, high pressure floor sib with a Tohatsu 5 HP 2 strokes engine to different lagoons which are located at five thousand meters high above sea level. From all high altitude inquired/answered issues, there are some recommendations: change for decreased lower jets numbers, the point is which jets to change; main jets, slow jets or both.

Some states that engines running at such altitude will perform horrible, some assures will not be able to even have a start. Engine losses about 12% of it's HP every 1,000 meters, so at that altitude will have lost 60% of it's HP. A decrease in propeller size pitch will also be needed to compensate a bit it's low rpm's. Wrote Toh tech dept inquiring about high altitude uses, their answer was: Sorry cannot help, our high altitude experience just goes to less then 3 K meters high as our Mount Fuji, the highest mountain in Japan is less then 3 K. Seems have taken an engine to test ?

Any ideas, comments are welcome, meanwhile untill there are appropriate tech answers available, all those big trouts will have to wait to be cooked. "Thumbs-Up"


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Old 11 October 2008, 16:22   #2
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Performance will definitely drop off - prob about 50% at that altitude.

This is why normally aspirated aero engines struggle much above 14,000' - the only real way is a supercharger or a turbo to get more air into the engine.

I seem to remember watching a diving prog at Lake Titicaca where they used either compressed air or oxygen to get the engine running.

You can try messing about with mixture settings but the main problem is the sheer lack of air. You need to lean out the mixture as much as you can to compensate for the lack of oxygen. Old aero engine used to have levers to adjust the advance/retard and mixture.

Try to use the hottest/richest fuel you can as well. if the area isn't too dusty take off the air filter.

I see Honda do different jets for high altitude use for their generators.

http://www.planopower.com/store/honda/eu2000i.shtml
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Old 11 October 2008, 16:39   #3
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What incredible pictures - I am REALLY jealous - I love far out places away from it all - awesome!!!
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Old 11 October 2008, 18:06   #4
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At 5000M, I'd be worried about the human endurance too -

http://en.wikipedia.org/wiki/Altitude_sickness

OK if your're used to it I guess?
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Old 11 October 2008, 19:33   #5
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I wonder if you would get better advice from off road bikers or snobmobile drivers as they are more opten used at altitude .
I know the user manual supplied by KTM for their 2 strokes has a lot of specific jetting info linked to altitude and temperature and the bikes come with a selection of different jets and needles as standard . maybe you could apply some maths and come up with what you may need , but do they even make jets that would suit , high altitude boating isn't that common surely .

What about electric motors ?

Awesome place though good luck
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Old 11 October 2008, 22:11   #6
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Now that's a good idea

http://www.torqeedo.com/en/hn/home.html



Pretty advanced stuff - of course you still have the problem of charging them - sunlight is pretty strong at that altitude but you would still need quite a lot of solar panels - they could be charged from an inverter attached to a vehicle though.
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Old 13 October 2008, 16:35   #7
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Thanks all for the input/ideas, etc. Would be too expensive to buy a electric motor, charger, converter, etc, for just one high altitude fishing. At that altitude will have a terrible headache called "soroche" if you walk fast, will faint, so better acclimatize well doing nothing, just trying to have decent breathing after arriving, have a nice coca tea, very good for altitude sickness.

Will write Yamaha and Mariner to inquire high altitude spare jets so to have a better opinion, if impossible to find, you still have the option of paying a local to row your sib, a very cheap option

Although have sold some Tohatsu 5/18 HP engines to be used on Lake Titicaca which is 3800 mt/a/s/l are performing much better than at 5 K height. Somebody told me that Bolivians lakers are changing carb jets to perform much better on their sea level engines, that is the eay to go along with a less size prop pitch.

Thanks for the nice comments of the lagoons, there are 50 on that area, some of them side to rural roads and easy for sib in-outs. This is one of my favorites...look for the shark...

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Old 13 October 2008, 16:46   #8
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Quote:
Originally Posted by Locozodiac View Post
have a nice coca tea, very good for altitude sickness.
The Coca Tea, eh?
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Old 13 October 2008, 17:40   #9
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The Coca Tea, eh?
Yeap! that's the way, but made from fresh coca leaves, not the white powder stuff....that's naughty, naughty...
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Old 13 October 2008, 18:02   #10
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You do need to be very careful at that sort of altitude. I have done quite a bit of mountain climbing and the altitude really saps your strength. Make sure you take some time to get used to it. Driving up to that altitude can be too fast - sometimes better to walk!!!

Get hold of some Acetazolamide or Diamox.

http://en.wikipedia.org/wiki/Acetazolamide

If you get ill get down quick - instant relief.

Good luck with the trip and take loads of pictures!!!
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