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Leaking carb

4x15mph

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Location
Downingtown, PA
Boat Make
Yamaha
Year
2018
Boat Model
AR
Boat Length
21
Started the engines today for the first time to prepare for the season. Both engines started although I noticed gas leaking from the one of the carbs of my port engine. I have isolated the leak to the areas with the arrows in the attached pictures. where the gas line goes into the 1st carb of the rack was suspect so i tightened that brass fitting. That didn't fix the problem.

After pulling off the flame arrestor etc, it seems like the leak might be from the gasket where you will see the 2nd arrow. I rebuilt these carbs last year using the SBT rebuild kits... is that coming back to haunt me?

Any advice on next steps or experience with dripping carbs? I am thinking I will rebuild this single, leaking carb with a genuine mikuni rebuild kit and replace just the gaskets, rubber seals, and diaphram.

I have to mention that I do have the electric, groupk air/fuel separator so my fuel is under pressure which may be adding to any carb gaskets giving out but I am afraid it may be an SBT thing.
IMG_1186.JPG
 
Last edited:

Speedling

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Cedar Lake, IN
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SS
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Picture not showing for me.
Only thing you can do is tear into it and figure it out piece by piece!
Hopefully it's evident right away.
 

4x15mph

Jetboaters Admiral
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Location
Downingtown, PA
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Yamaha
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2018
Boat Model
AR
Boat Length
21
Thanks @Speedling . I reposted the pic so that should work now. Sorry it is sideways

I went ahead and ordered a genuine Mikuni carb kit so I will rebuild and give it a shot.
 

4x15mph

Jetboaters Admiral
Messages
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Reaction score
1,076
Points
257
Location
Downingtown, PA
Boat Make
Yamaha
Year
2018
Boat Model
AR
Boat Length
21
Rebuilt the suspect carb with genuine Mikuni kit and replaced the fuel line and return line between this leaking carb (#1) and the next one in line. When reattaching the fuel lines, I used a smaller hose clamp since this was one of the "suspect" problems. I also removed the "suspect" brass nipples for both the fuel source and return line, applied aviation gasket sealant, and threaded back in.

I ran the boat for 10 minutes on the hose and the leaking carb/hose/nipple is no longer leaking. So great that this is behind me and the boat is ready for the season.
 
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