Help needed! Mystery Carb

[Itbrokeagain]

I picked up a cheap 1990 Sea Doo SP 580 last week, and after a bit of tuning and bew plugs she was running pretty good. Even pulled a tube! I got home that night and pulled the 'sending unit' (hoses) off the top of the tank to get a better look at how much gas we used to get an idea of what to expect from the machine. One of the pick up hoses cracked off. No biggie. I cut it a little shorter and stuck it back on. Cracked it over, it fored right up and then died, as expected, when it hit the air bubble in the line.

Thing is... that was a week ago. And it still hasnt ran off its own fuel since.

I found out i put the pick up tube on the wrong spot and got straightend out but still nothing. The pump shas fuel to it... and some comes out but im not sure if its enough honestly. Anyway, ive ordered a new fuel water seperator/filter aftaid it was letting air in. And it was NASTY. Also a pump rebuild kit. But heres where i need help.

*important part below*

The carb on this craft doesnt seem to exsist. Its a Mikuni with the number 995 and 956 stamped into it, but i cant anything online for a numer, rebuild kit, anything. No internal pump. Ill put a link below to a picture of an identical carb, filter, and pump, minus the black air box on top of the carb. I should mention this is a yellow 587 type motor that is suspiciously clean. What i need from you guys is any help identifying this thing! Thank you!!

 

[Itbrokeagain]

Dammit i forgot to link the photo. I had one job...

https://www.google.com/search?q=199...a+doo+sp+580+round+carb&imgrc=nUab7400fGT2-M:

 

[wfo speedracer]

Thats a stock Mikuni 38 BN carb used on Seadoo from 1988-1990 in 91 the changed to the SBN 38, it is only used on Seadoo's m y suggestion is to upgrade to a newer style SBN 38, I have some used one laying around here, it is a direct swap, all cables hook up the same you will not use the external fuel pump however as the SBN has an integral fuel pump.

 

[Itbrokeagain]

Thats what i thought too but this one is different. Any bn 38 rebuild kits have way more parts than this has. There no square gaskets, and only 1 diaghram and seal that i can find. Also this one has way more screws than the round 4 screw design

 

[kevinz]

If it helps, I think that the Polaris blue triple Fuji engines used the same carbs, I had a set from an SLT 780 I sent to a freind who needed them for the same seadoo you have...

 

[wfo speedracer]

Thats what i thought too but this one is different. Any bn 38 rebuild kits have way more parts than this has. There no square gaskets, and only 1 diaghram and seal that i can find. Also this one has way more screws than the round 4 screw design

Reread my statement these carbs were specifically made for Seadoos, I have been into a zillion of them they also have an externally replaceable main jet, nothing mystery or rare about them they appeared on every Seadoo made from 1988-1990.

 

[wfo speedracer]

If it helps, I think that the Polaris blue triple Fuji engines used the same carbs, I had a set from an SLT 780 I sent to a freind who needed them for the same seadoo you have...

Polaris never used these carbs, they used triple SBN 38's with a block on the back to tie the carbs together , then they used a single external fuel pump to feed all of the carbs.

 

[RodInEscondido]

Thats a stock Mikuni 38 BN carb used on Seadoo from 1988-1990 in 91 the changed to the SBN 38, it is only used on Seadoo's m y suggestion is to upgrade to a newer style SBN 38, I have some used one laying around here, it is a direct swap, all cables hook up the same you will not use the external fuel pump however as the SBN has an integral fuel pump.

The carbs you have around are from single-carb installations? In my playing around with a pair of carbs from dual-carb installation they are marked mag and pto with the non-fuel-pump carb with output restriction to maintain fuel pressure across both carbs and the fuel-pump carb with no output restriction. Looks like the output restriction for dual-carb installations can be placed anywhere in the return line ... experiments/questions remain. For another thread, do not want to sidetrack this one too far. Maybe a PM to check on price for the carb(s) you have.