Carb talk and info needed...

[Guest_User]

Please feel free to add content:

1998 Challenger 1800
carb model: Mikuni Diaphragm BN-40i-38 with accelerator pump

I have been told that these NEW 40mm Mikuni replacements from WSS can be used with little modification on the 98 challenger 1800. I`m just guessing that it is the fuel lines orientation as those carbs have the fuel pumps attached. I have just a fuel supply end plate and no pump on the MAG carbs... These are listed for the 97 and 99 model year but NOT the 98 1800.

http://www.watercraftsuperstore.net/PWC-Caburetors-Carbs/714HP002.html

specs:
MAG side carb has the following:
Low jet 67.5
Hi jet 140
needle valve 1.5
arm spring 95 gram
low speed screw set at 1.25turn out
hi speed closed

http://www.watercraftsuperstore.net/PWC-Caburetors-Carbs/714HP003.html

specs:
PTO side carb has the following:
Low jet 67.5
Hi jet 142.5
needle valve 1.5
arm spring 95 gram
low speed screw set at 1.25turn out
hi speed closed
Accelerator pump added to PTO carb


The specs from the OEM carbs from the shop service manual:

Main jet MAG: 142.5 PTO: 145
Pilot jet 67.5
Adjustment Low-speed 1-1/2 turn ± 1/4
High-speed screw 0

To make these replacement carbs work is it just a simple jetting change to the factory specs?
I can deal with the fuel supply changes by reusing my fuel supply end plates/caps, and removing the pumps on the carb body`s. ( I have remote fuel pumps).

Please educate me in these Mikuni carbs. I don not know what can be interchanged within the same model carb.
Thank you...PR...

 

[Matt Braley]

Hey Pale. You have long since taken the "builder's choice" in your modded boat project. Why not just clean up two sets of stock 96XP carbs to spec and go that way? I'm thinking $200 would buy 4 clean carbs, right?

 

[Guest_User]

Hey Pale. You have long since taken the "builder's choice" in your modded boat project. Why not just clean up two sets of stock 96XP carbs to spec and go that way? I'm thinking $200 would buy 4 clean carbs, right?

well I`ve already invested in all new Mikuni kits that are installed, new needles and seats, pumps etc and the time to clean meticulously and reassemble. 2 Mag carbs had sticky throttle syndrome, so apart the shafts came for cleaning. upon assembly of one carb, a single throttle plate screw decided it was time to have the head snap off just after tightening was achieved. Dam...
At the time I did not know if this boat would leave the trailer so I pulled a podunk cheater trick and just layed a little 2 part into the area where the screw head resides flush. It has run this way all season with no issues. Im just not jiggy with the fitting repair and the single broken screw and the work needed to repair correctly. I know a great source for repair on the west coast if that were the route chosen.
The issue I have with the set is that the PO had made sent the carb out for repair, instead of using the correct mikuni T, he had a machine shop do something to fit a brass 90° fitting facing towards the front. this is the return line. That is also secured with some epoxy...hmmm ok, it works but still not the way it should be inspite of all the crazy crap I had to deal with in this boat.
with that said, I`m either looking at sending these out for professional repair to restore the set, or simply replace with "new" set up correctly and call it a day...
Buying used carbs and rebuilding would be one step down from what I have now... The interior of the carbs are spotless...
Given the efforts in this project I think fuel system warrants an upgrade...
what would really suck if some unforseen engine failure occurred after all was said and done and the coin invested...
It might just then become a NJ reef...:nopity:

 

[LouDoo]

Hey Matt,

You know what really bugs me? Guys that keep changing their avatar's, what do you think?

Lou

 

[Matt Braley]

Well Lou....it looks like just another"sister". After the original it just all starts to fade.

 

[racerxxx]

Andy,

These guys restore carbs and are also a Mikuni dealer. You might want to reach out to them to see how much to resto your carbs.

http://www.seadoocarburetors.com/

I think they are $195 for the new carbs your looking for and $150 to redo yours--I just wonder if that is a complete resto, paint and all.

 

[Guest_User]

Andy,

These guys restore carbs and are also a Mikuni dealer. You might want to reach out to them to see how much to resto your carbs.

http://www.seadoocarburetors.com/





I think they are $195 for the new carbs your looking for and $150 to redo yours--I just wonder if that is a complete resto, paint and all.

awe man, they don`t carry my model number... dam...

BN40i-38-30
BN40i-38-29

 

[CaptSteve]

I used those guys. I sent them my carbs and they rebuilt them. Got them back clean, repainted, and working perfectly. Even if your carb is not listed, they will re-man what you send them. I told them what jet size, pop-off, etc. They set them up to OEM specs.

http://www.nationalcarburetors.com/seadoo/mikunicarbs.aspx

 

[racerxxx]

Cool that's the same place.

Sent from my SGH-T989 using Tapatalk 2

 

[Guest_User]

Hey Matt,

You know what really bugs me? Guys that keep changing their avatar's, what do you think?

Lou

:toetap05:

 

[Guest_User]

Cool that's the same place.

Sent from my SGH-T989 using Tapatalk 2

I heard back in an email, unfortunately they do not carry those models carbs, dealer only... yay, not...lol...
also inquired about the repairs if possible.

 

[Guest_User]

Racerxxx thanks for the helpful info! :thumbsup:
you know what really bugs me, Threadjackers...:bs: