300/440/550 js550 sbn carb issues

[SMOS]

fresh rebuild,150psi compresion,1mm overbore,milled head,jetco pipe and exhaust manifold,mariner water box,stator rebuilt by jetski solutions new plug wires,and a new sbn carb,the problem is it is hard to start,when looking down carb can see fuel running into venturi,the carb has a 2.3 needle/seat,have tried smaller pilot jets still same(pilot is a 88 now),anyone have any sugestions,the motor also has a ocean pro vortex air filter,is also set up for dual cooling

 

[Kohldanielzimmer]

Perhaps your pop off pressure is too low with the 2.3 n/s. what spring are you using?

 

[Quinc]

What spring do you have?
Most threads I've read say to have the pop off around 18-22psi

http://www.x-h2o.com/threads/42190-Mikuni-Spring-Color-amp-Popoff-Pop-Off-Chart

 

[amitchell]

I used 2.0NS black spring, 95L 120H with 44sbn on a 550 with full pipe and 175psi comp.

 

[SMOS]

the spring is shiny silver,picked up a 2,0 n/s and the other 3 springs,going to replace the n/s and try the blace spring with a 95 pilot

 

[dunnville jetbum]

you want to have around 17 psi for pop off pressure. Go to the vintage section at pwctoday, search sbn carb settings, you will get the exact n/s, jets etc. I ran those specs on my 550 and it runs mint, nice and smooth, didnt have to play with jets at all. They are hardcore vintage guys on that site they know there stuff over there

 

[dunnville jetbum]

you said about the fuel leaking, you n/s is prob leaking and letting fuel in. Check the silver pivot arm, it maybe bent and the needle isnt seating right, and allowing fuel to run into carb