94 xp pop off setting ultra rare spring

[Jakeo625]

So here's my issue is rebuilt the carbs with osd back to oem followed the rebuild thread to a t. They specify to resue old spring no big deal. Did leak check and all tests pass except pop off. My issues is the spring which I determined by swapping faulty spring and low pressure followed. The oem spec is 16-21 psi for the 94 Xp I'm at 23 psi on one carb and 12 on the other. The spring is about as rare as unicorn horns part number 270500242 the lowest spring 65lb mikuni with my 1.5 needle and seat would give me 30ish pounds on pop off what do I do? Am I just completely screwed or what I have way to much invested in this jetski to let a $3 spring be the end please help

 

[Jakeo625]

Bump?

 

[tobytd]

Google : Mikuni Super BN carburetor manual
Check pages 15 and 18.
Hope this helps

 

[Jakeo625]

So if I swap to 2.0 needle and seats and black springs do I need to change any other aspect of the jetting? Or is the pop off pressure all that matters? It seems so easy looking at it now i appreciate the info plus the manual definitely will come in handy.

 

[tobytd]

@mikidymac ..help us out

 

[Jakeo625]

So along with the question of whether i need to change other jetting aspects when switch to the 2.0 seat is there a difference in needles? My 1.5 needles have never been ran and I can save about $10 buy just 2.0 seats. I know the seat orifice is different but are the needles also?

 

[Jakeo625]

To add to this I did some deep diving on the forum last night and found this thread where mikidymac says I shouldn't change the needle and seat to a larger size. So I'm at a loss here how do I get the correct pop off 16-21 when the unicorn horn spring is non existent? Using even 65 gram springs according to the chart would get me around 32psi which is way higher than what is specified.

H

Thread 'Carbs from hell!'

Jun 1, 2020

I can't get these carbs to pop off right at all.

1996 seadoo GTI.

Problem is, the needle and seat won't seal up right. I rebuilt them once before with SBT kits. When setting the pop off pressure, it always leaked just a little before the pop off pressure would hit. I didn't think it was a big deal because it was just a little and only a few psi before target pop off. Threw them back on the ski and its got a no start now...I'm assuming the engine is flooding because the needle/seats are leaking.

Came here and did more research and bought genuine mikuni kits. They do NOT come with the...

• Hoiyay
• Replies: 24
• Forum: 2-Stroke Sea-Doo PWC Forum

 

[shamrock246]

You can bend the arm up that would lower the spring pressure and might bring you in range, I think you can be up to 1mm from level with the housing.

 

[Jakeo625]

That would lower the good spring but I would need to bend the bad spring side quite a bit to get it up to correct pressure. The bad spring is about a light 1/8 heavy 1/16 visibly shorter than the good spring which is why I'm inguring about what to do. There's some sort of damage or it's just plain worn out on the one spring.

 

[Jakeo625]

Can I gain 10psi bending the arm down without messing up the needle? That's one thing I kept reading was it would mess up needle travel if bent to far which is why I havent touched the arms

 

[tobytd]

Pop off is just a test to see if the needle seat can be lifted by pressure and reset to seal. I would use a 2.0 needle seat with a black 80 g spring. That should give you a pop off pressure of 21, which is what you’re looking for. Start with the low speed screws one and 1/2 turns out. And I would open the high speed screws slightly. Too rich is never a problem, you can always take away fuel