Help choosing the right aftermarked carb for SeaDoo SPI 587 single carb Rotax motor

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myren

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Hi Everyone

I am the happy owner of an old SeaDoo SPI which I am renovating here in Denmark. There are not many of them here in our country.
It is a SeaDoo SPI with Rotax 587 single carb engine.

It was equipped with a mikuni 34mm (round type, which I have renovated), but it has broken in the aluminum, and it did not run super well. It was an older type where the petrol pump sits separately

I'm in doubt which carburetor will fit that engine. i would like a newer model where the petrol pump is included.

The inlet is 38mm and there is 57mm between screw holes

I have found 3 different ones that I think may fit

1) 34mm
Mikuni Super BN Series Carburetor 34mm BN34-28-8010 BN34288010 13-5057 | eBay
2) 38mm
Mikuni - BN38-34-8113 - Super BN Series 38mm Carburetor for sale online | eBay
3) 40mm
Mikuni BN40I Carb Carburetor Sea Doo 717 720 GS GTI GTS Sportster Challenger | eBay

Or maybe a completely different one
So I hope there is someone out there who has some input

/Tue
 
I have a BN38 very similar to the one you have the link to on my 93 GTS with a 587 and love it. Note that one in the link uses a primer system instead of a choke. VERY easy to install and inexpensive, and I actually like it better than a choke.
 
BBird said:
I have a BN38 very similar to the one you have the link to on my 93 GTS with a 587 and love it. Note that one in the link uses a primer system instead of a choke. VERY easy to install and inexpensive, and I actually like it better than a choke.
Click to expand...
The BN38 was also my first choice... but in the review on ebay a guy wrote:

"Had to change the jetting from my stock carb to make work correctly for a 95 Seadoo SP"

But you did'nt have that kind of issue i guess
 
I did, but I always assume that I will have to put in the correct jets, so I was prepared for that.
 
OK, I am not that much into carburetor adjustment, I can adjust Hi And LOW needle :)
But I have now been reading a little about "jetting", so I understand that i might change them if the needle has too many/less turns for right mixture
I guess you have to buy these separately.

I can find a lot of Mikuni jets kit, but not a kit for the BN38.

What sizes did you end up with for HI and LOW?
Can you link to a site where I find the correct jets?
 
The jets are very easy to replace with the right size flat screwdriver for each. Happy wrenching!
 
Thanks... that really helped

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Maybe you can explain why the engine (587) together with the the BN38 carb have so many different settings. Same motor and same carb??
 
I have wondered that myself. I have a 92 and a 96 GTS and they are basically the same, but have different jets. For testing, I used the 96 on the 92 and didn’t notice much difference.
 
BBird said:
I have wondered that myself. I have a 92 and a 96 GTS and they are basically the same, but have different jets. For testing, I used the 96 on the 92 and didn’t notice much difference.
Click to expand...
The only thing that I can think of is the impeller might run best at a specific speed for each model.

The SPI has a stainless impeller

But... ok... I am not the only one to wonder
 
Do not drill out jets!

Get the correct jet for your application, Seadoo tells you exactly what to use.
 
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