Jet sizes for different altitudes

[garyjgriff1]

I need to change the jets in my df2.5 Suzuki carburetor. I want to go to a higher altitude. Any help would be appreciated.

 

[Scott Danforth]

how much of an altitude change are you concerned with. not sure a 2.5 has replaceable jets

 

[boscoe99]

The Suzuki parts catalog indicates optional pilot (idle mixture) and main jets for the DF2.5 model. One under size and one over size it appears. There are probably other Suzuki or non-OEM jets that would work.

The change in jet size will be a function of the altitude at which the motor will be operated. 3000 feet MSL is one thing.10,000 feet MSL is something different.

As important as changing the jets is to make sure an adjustment is made to the propeller pitch. Even with a jet correction the motor will be making less HP. So the pitch of the propeller needs to be changed based on the HP loss. Again, a function of the altitude.

 

[fishrdan]

What elevation and is the boat always going to be at that elevation?

- If always at high elevation, swapping jets AND a lower pitch prop would be appropriate.
- If temporarily using the boat at high elevation, swapping jets may not be the best solution since the jets would be changed back before running at low elevation again (lots of work). I'd just use a lower pitch prop for the short time at altitude.

If the outboard is run at low elevation with the high altitude jet(s), you could burn up the outboard, melted piston(s)...

I make trips to high altitude, but mainly use the boats at low altitude. In my little boat, I just swap props, 15 minutes and done. My big boat gets everything (jets, timing, prop) before heading to high altitude since it makes a HUGE difference, but that all has to be reversed before running at low altitude again. Lots of work....

 

[Sea Rider]

If altitude is less than one thousand meters / 3300 ft high just need a less pitch prop to compensate the slight power loss. Some other brands have jet kits for higher altitudes in increments of one thousand meters for each kit along a less pitch prop. OB won't perform spot on as boating at sea level, but will work much better than doing nothing..

Happy Boating