Mikuni BN38 carburetor

[caw0215]

Hi- I've ordered and installed rebuild kits on a 1995 seadoo XP 717. I've also ordered and installed new jets (MAIN-135 PILOT-67.5) and 1.2 Needles for both carbs. I've seen different sizes being discussed but decided to try to get back to stock as closely as possible.

What concerns me is my pop off pressure for both carbs is around the low 20s. The carbs hold pressure fine and other than the low pop off it seems OK. But the guide I referenced says it should be 40-60. ( URL was blocked by this forum but it's on seadoosource website.

Should I try to get new springs to get higher pressure? or am I ok with the lower pressure settings. I've no idea what size the original springs are but guide suggests 80 or 95 gram needle valve spring is standard.

Also to confirm the adjustments LOW- 1-3/4 HIGH- 0

Thanks in advance.

 

[mikidymac]

You have something wrong as even with the lowest spring that Mikuni makes which is 65 gram and your 1.2 needle and seats you should see 47 psi.

The correct springs for your ski are the Black 80 gram springs which should put you at the mid 50's and within the 40-60 range.

1. I would first verify you are using genuine mikuni parts.
2. Your gauge is correct.
3. Are testing with the seats wet with WD-40 on each pop test.
4. Make sure you are using new needle arms and pivot pins and they aren't bent.
5. Get new 80 gram springs if steps 1-3 are correct.

 

[caw0215]

ok thanks will run thru those steps

 

[matempl]

I just did both carbs on my 95 xp with kits from osd. My pop off was 58 on both

 

[caw0215]

OK to be sure I've ordered black 80 gram springs. Can you recommend where to order genuine 1.2 needle and seats? majority of what I find online is replacement not OEM-Thanks

 

[mikidymac]

Here you go...Genuine Mikuni 1.2

 

[caw0215]

Thanks will rule things out 1 by 1.

 

[caw0215]

lesson learned. The springs didn't make much difference but the mikuni 1.2 needle and seats you recommended now have me at 40-43 pop off psi.
Thanks -
Carey