Tohatsu High Altitude Jets Kits

[Sea Rider]

Was reading some HAJK data but only for 3300 to 6600 feet above sea level. Standard jets for sea level operation for the Tohatsu 2 strokes M5B model are : Main Jet : N? 78, Slow Jet N? 52

Asume if going higher, will need lesser diam for both jets, right ? would a less or more prop pitch help in pushing better a small boat located at 10 to 15 K ft, than the standard factory prop?

Happy Boating

 

[fishrdan]

Re: Tohatsu High Altitude Jets Kits

Are you going to run at 10-15K' all the time? For that altitude I bet you are going to need to re-jet to get it to run right, smaller jets. Less prop pitch will have a greater impact on performance than smaller jets though. Be aware, you are loosing about 3% HP every 1000'. At 10,000' the OB is loosing 30% if it's rated HP, 15,000' the OB is loosing almost 40% of it's rated HP.

I've run a couple boats up at 8,800' and the performance loss is very noticeable.

 

[Sea Rider]

Re: Tohatsu High Altitude Jets Kits

Yes we have boaters located at those mentioned altitudes like Lake Titicaca for example, they knew about the noticeable power and performance loss before buying their engines. It's much better than rowing seems there's not available factory jets for those altitudes, even Tohatsu does not have experienc on high altitudes issues as Mount Fuji is only 2,000 meters high. I knew there was a power loss of 10% each 1 K meters high, so near 50% off at 5 K.

Happy Boating