Elevation Issues

[Dwaters]

Hello,

I am having an issue with my ski running. There is a hesitation between the low end and the high end. In my past experiences this was caused from the pop-off. After talking with Pro-Tec, I was recommended to change the prop from stock to a 13/18 pitch.

Everything on the ski is stock and I’m riding at 5600’ elevation (Boca).

Am I being lead in the right direction?

Thanks y’all

 

[Quinc]

What year superjet? And yes a lower pitched impeller will help. Have you taken your carbs off and tested the pop off? You could probably get away with going down a jetsize as well.

 

[88kawi5fiddy]

Hello,

I am having an issue with my ski running. There is a hesitation between the low end and the high end. In my past experiences this was caused from the pop-off. After talking with Pro-Tec, I was recommended to change the prop from stock to a 13/18 pitch.

Everything on the ski is stock and I’m riding at 5600’ elevation (Boca).

Am I being lead in the right direction?

Thanks y’all

what kind of hesitation? ride at 1/4 throttle or such for about 30 seconds then pin it wide open.
If it shuts off, its a lean bog, popoff too high.
if it burbles and coughs and slowly starts to go faster WITHOUT feeling like it shut off, then takes off and starts running well, the popoff is too low.

the impeller doesnt have poop to do with this. you'll lose a couple hundred RPM or so on the top, has nothing to do with the bottom.

 

[WFO Speedracer]

Dropping impeller pitch is quite common in higher elevations, as is raising compression , carb adjustments will also be needed Reno is at 4505 ft , its way way up there.

 

[Dwaters]

What year superjet? And yes a lower pitched impeller will help. Have you taken your carbs off and tested the pop off? You could probably get away with going down a jetsize as well.

View attachment 448451

Hello!

I have a 2005 Superjet. I’m about to take the carbs off today and check pop off. I will update when I’m done.

 

[Dwaters]

what kind of hesitation? ride at 1/4 throttle or such for about 30 seconds then pin it wide open.
If it shuts off, its a lean bog, popoff too high.
if it burbles and coughs and slowly starts to go faster WITHOUT feeling like it shut off, then takes off and starts running well, the popoff is too low.

the impeller doesnt have poop to do with this. you'll lose a couple hundred RPM or so on the top, has nothing to do with the bottom.

Thank you for your response.

When I pin it after a 1/4 throttle it wants to fall on its face and die. Occasionally it will be fine when I’m on plane.

 

[harrymank]

Superjet
125 high
75 low
1.5 ns
95 gram Dull silver

This is what I have written down for my Superjet.
701 with a head, dual 38’s, and a pipe.
I’m at 4300ft it’s hard to ask jetting questions when everyone is at sea level.

 

[88kawi5fiddy]

Thank you for your response.

When I pin it after a 1/4 throttle it wants to fall on its face and die. Occasionally it will be fine when I’m on plane.

lower your popoff. it is too high, taking too much pressure to flow the fuel.