Freestyle Is plug reading completely useless on a freestyle ski?

[Storbeck]

Or maybe I suck at tuning?

I seem to end up with a rough pattern of going down on the low speed jet until I get a hesitation, then up a little so I don't, then down on the high speed jet until I don't feel like it's doing anything, back to the low speed to make sure the high speed didn't affect it, then as long as there isn't something about the way the ski runs that I don't like, I'm pretty much done.

This always seems to end up with a low speed jet that is rich of "ideal" I've got four stroking and and the plugs always come out looking way rich, because most of the time the ski is not wide open so it is in the rich low speed part of the carb jetting. Going leaner (on the low speed) gets a hesitation.

Doing a plug chop is completely out of the question because I can't hold this thing wide open for any length of time.

So, is plug reading completely useless on a freestyle ski?

For those who have actually tuned a ski that has a motor/hull combination that can't be held wide open, do you do something different?

 

[Sparkplug]

Piston wash and the 1/4 throttle test are the best ways to tell if your engine us getting the proper amount of fuel through the circuit transitions. Any other way is just guessing.

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[Storbeck]

Piston wash and the 1/4 throttle test are the best ways to tell if your engine us getting the proper amount of fuel through the circuit transitions. Any other way is just guessing.

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Seems like piston wash would have the same problem as the plugs.

How do you determine that you have the right high speed jet?

 

[Sparkplug]

Your piston wash will be even

Piston wash should develop fairly quickly. And the pattern very apparent. And similar between both cylinders.

High speed circuit jetting. 1/4 turn fat. 1 minute wide open. Pop the head. Examine pistons. Tune and repeat. Should not take.more then 3 or 4 times. Once dialed. Its set for life at that altitude.

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[Storbeck]

I guess you're agreeing about not relying on plugs.

But either I'm not understanding or you're not understanding. Holding wide open not an option. I know you have mentioned having an 1100, are you holding your 1100 wide open for a minute?

 

[Hirschfelt]

I think a tire around a post at the dock and nose your ski in would be an option for high speed test.

 

[fx1mark]

This is a good carb tuning video. I did my tuning at a boat ramp during the week when no one was there. Just left the ski strapped down on the trailer. I had a tiny tach aide me in the low speed tune. For the high speed tune you could also ride it wide open and hit the kill switch then swim the ski back in to shore.

I also have these on my carb tuning screws. Much better than trying to fumble around with a screwdriver.

Extreem Throttle Billet single mikuni carb adjuster knobs

www.extreemthrottleinc.com

 

[Storbeck]

This is a good carb tuning video. I did my tuning at a boat ramp during the week when no one was there. Just left the ski strapped down on the trailer. I had a tiny tach aide me in the low speed tune. For the high speed tune you could also ride it wide open and hit the kill switch then swim the ski back in to shore.

I also have these on my carb tuning screws. Much better than trying to fumble around with a screwdriver.

Extreem Throttle Billet single mikuni carb adjuster knobs

www.extreemthrottleinc.com

Do you have a rough idea if the rpm you were pulling stationary was similar to what you were getting moving on the water?

 

[kevbo]

For freestyle engines you can open the top screws until power falls off then slowly close them until its restored. A tachometer is very helpful for this. Usually, too lean will cause a hesitation and too rich will be down on power. Freestyle engines often require overly rich pilot jets so plugs tend to end up dark. Its very difficult to burn a piston if the mixture is rich of peak power.

 

[fx1mark]

Once I adjusted the low speed screw then I adjusted the idle screw for the correct idle. I then adjusted the idle again once it was in the water. So, no, I don't know what it was. I found it hard to tell when the rpms went up when I was turning the low speed screw in and the tach made it easy to tell.

 

[Storbeck]

For freestyle engines you can open the top screws until power falls off then slowly close them until its restored. A tachometer is very helpful for this. Usually, too lean will cause a hesitation and too rich will be down on power. Freestyle engines often require overly rich pilot jets so plugs tend to end up dark. Its very difficult to burn a piston if the mixture is rich of peak power.

You have gotten a hesitation from the high speed being too lean? I have definitely been able to make it hesitate with low speed, but have not with high speed. I've never tried to go very lean on the high speed jetting though because I'm skeerd.

 

[kevbo]

The bottom screws are for the low idle mixture only, I set those out of the water and rarely have to touch them again. Every rider should open their top screws and set them a little rich of peak power. Top ends will last a very long time if you do this.

 

[Storbeck]

The bottom screws are for the low idle mixture only, I set those out of the water and rarely have to touch them again. Every rider should open their top screws and set them a little rich of peak power. Top ends will last a very long time if you do this.

I may have misunderstood you. I'm very well aware of what the two screws do. I thought you had said that you have experienced hesitation from the high speed screw/jet being too lean. I have only experienced that from the low speed being too lean, I've never seen it from the high speed, which is why I asked.

 

[kevbo]

Oversize pilot jets and low popoff may prevent hesitation even if the main circuit is a little lean of peak power. This condition may work for freestylers but its very dangerous whenever full throttle is held for very long.

 

[waxhead]

To be its about as useful as a plug chop on any ski.
So while its useless its no more useless than any other ski

 

[fastgtfairlane]

technically to do an accurate plug chop, you need at least a 10x magnifying glass to really see whats going on. this would be for more race orientation though.

 

[Sparkplug]

Peak rpm is how most tune the high to the exact spec for given altitude and Temps. You need a tach to do it. Get peak rpm. And richen 1/8 turn for safety.

Anyone can tie their ski to a dock and simulate wot. I have the same type of ski. Super short. Super powerful. You can nose it against a lifejacket on a trailer and do the same thing. If you can't run it under load at full fuel and air, then you have no real way of knowing your tuning is correct.

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