Jets

[seadoinit]

Are there jets for the low speeds?

Thanks,
Eric

[Technical Support]

Re: Jets

For most carbs, yes.

[seadoinit]

Re: Jets

so that means i could lean out the smaller jets a little to which would give me better performance off the line???

What do people generally do when purchasing new jets, do they start off with buying jets for the highs or lows first?

eric

[Technical Support]

Re: Jets

Jetting is matched to the needs of the ski. If you install freer flowing aftermarket carbs and/or flame arrestors, you will need to jet up to increase fuel flow. THere is only one correct carburation for any ski. If you are too rich, yes leaning will give you better performance. However you do not want to run too lean - not only will performance suffer, you can do engine damage. Lots of people think leaner = better performance. That is only true if you are too rich to begin with.

[seadoinit]

Re: Jets

I have an aftermarked flame arrestor and the stock jets are still in the carb. Do you think i need to get smaller jets?

thanks,
eric

[Technical Support]

Re: Jets

No, as I said - you need larger jets - MORE fuel for the added air of the aftermarket flame arrestors. You are running too lean if you put on aftermarket arrestors and did not rejet and/or turn your needles out.

[seadoinit]

Re: Jets

reason i said that was because you used the term "jet up" i didn't know that meant "larger Jets" sorry, just a newbie here.

Whats the deal with the pop off pressure and springs, just when i thought i had a full understanding along comes something new to the equation.

thanks,
eric

[Technical Support]

Re: Jets

Read the pop-off pressure tech article - along with all the others.

[1fastski.com]

Re: Jets

needing differnt jetting all depends on what ski your running , some can be ajusted , just remember one little mistake and POOF you have a hole in your piston { ever see the moive gone in 60 sec } lol it takes less then that to put a hole in a piston if you run to lean .

[Bill O'Neal2]

Re: Jets

When installing aftermarket spark arresstors ( aka, AIR FILTERS ) that are less restrictive than the oem spark arresstor system, you do two things to the calibration of of the carbs that effect the air/fuel ratio.

Less restriction above the carbs equals less vacume created through the intake tract, including the carbureators. PWC carbureators use the air flowing through and the vacume created to draw the fuel from the low and high speed jets ( that is why the carbs distribute more fuel when you cover the opening with the choke and the motor runs richer).

Because of a lesser amount of vacume, a lower pop off pressure is generally needed to allow the needles and seats to react quicker and provide fuel to stop the hesitation when accellerating that usually accompanies the installation of the new spark arresstors.

The second thing is the additional air flowing into the motor. This changes the air/fuel ratio even more, and is generally brought back into the proper ratio by increasing the jet sizes to compensate for the change in the ratio.

Removing choke plates when installing a primer kit also reduces the obstruction in the throat of the carbs and can also change the air/fuel ratio.

[seadoinit]

Re: Jets

thanks, great explanation, learning more everday. I do have the aftermarket flame arrestors and a primer kit maybe this is why i'am getting that slight hesitation when i give it full throttle right away. Can you give me the size jets i should get and the springs for the pop off pressure thing? Keep in mind i'am looking to get more performance out of the ski.


Eric

[Bill O'Neal1]

Re: Jets

Typically, raising the low speed jet size up one notch and lowering the pop off by using the next size bigger needles and seats with ensure you get enough fuel to rid yourself of the hesitation. Do not use less than an 80 gram spring or the motor will be difficult to get started.

[seadoinit]

Re: Jets

can you give me the size though so i know what i'am looking for in the catalog. I have no idea of what the stock size is for the high & low speed jets?.

thanks,
eric

[Bill O'Neal1]

Re: Jets

I might if I knew what engine you are working on and I was at work where I have manuals and notes. Why not just look at them and read the numbers so there is no mstakes ?

[seadoinit]

Re: Jets

oh, i didn't know they put the numbers on the jets? I'll take a look and let you know what they are.

thanks,
eric