what kind of carb is on

[rockymtndooer]

I have a 1997 Challenger 1800 with twin Rotax 787. I want to rebuild the carbs and put in new jets. What kind of carb is on it? I see rebuild kits for Mikunis for sale but they list numbers 44, 46 etc. What size jets were originally in. They were replaced once and my mechanic says that SeaDoos should have whatevere was originally in place no matter what altitude the boat is used at. I use it at 4,ooo ft. Also what kind of needle and seat. Bill are you there? Please help.

[frankey01]

Re: what kind of carb is on

Bill is probably done for the night just buy the mikuni SBN carb kit you will be fine. Illhave to look up the specs on the needle and seat and the jets maybe someone knows it by memory. Should be 1.5 or 2.0 most likely on the NS

[Technical Support]

Re: what kind of carb is on

sbn

[rockymtndooer]

Re: what kind of carb is on

I found a website that said Mikuni SBN so you are right on that. Another said turn the valve 1 3/4 plus/minus 1/4. But that would be for sea level I presume. How much should I turn in to adjust for 4,ooo feet elevation? Also should I put the stock jets on or get a different size. The local Sea Doo shop put on a diff size but a great jetski mechanic at a private shop said no use the originals and turn the valves in to accomodate for altitude. Any thoughts?

[Bill O'Neal2]

Re: what kind of carb is on

The type of carbureator ( diaphram type) used on watercraft adjust themselves pretty much for altitude increases, so the mechanic was right, only turn the adjusters in a little at altitude.

Use a lower pitched prop, 87 octane fuel and your watercraft will perform much better at higher altitudes.