78 Jag - carb leaking like crazy! - Snowmobile Forum: Your #1 Snowmobile Forum

9C1 · 09-16-2012, 05:00 PM

I'll preface this by saying this snowmobile ran fine last winter except I noticed this little bit of gas dripping super slowly from the outside bottom of the carb after riding. Figured the gasket to the bowl was leaking so I just put a new one on. I also replaced all fuel lines and put a new gasket on the fuel pump.
I also just sprayed carb cleaner in every hole on the carb and made sure everything looked clean.

Anyway, I got it all back together and the sled runs fine - except after about 10 seconds of running the gas will start shooting out of a hole on the top rear of the carb (where the air filter would attach), and it sends a stream of gas off toward the right side of the engine bay. Gets much worse the more throttle I give it. The whole carb is soaked on the outside after a brief running. Any help to fix this is much appreciated. Did I screw up the gasket on the float bowl or is something else wrong?

**BC_Dan** · 09-16-2012, 06:36 PM

First thing I would check is the inlet needle/seat. Then check the float to make sure it's set correctly or isn't sinking. It sounds like the inlet needle isn't shutting off.

**RJ Gleason** · 09-17-2012, 05:07 AM

Is it coming out of the side, or through the throat?
A pic might be of some help.

9C1 · 11-18-2012, 06:55 PM

Gas coming out of the spot at the end of the arrow (hopefully this pic will show up):

**RJ Gleason** · 11-18-2012, 07:51 PM

Over flow vent.
That points to the floats either being saturated, or the needle valve is not sealing off the flow.

9C1 · 11-18-2012, 09:04 PM

I'm new to carb repairs...I think I could replace the float, but how do I address the needle valve?

Rczr600rider · 11-18-2012, 09:13 PM

Remove the float and the needle is held in with a clip. It pops right out.

Viktory2k1 · 11-18-2012, 11:45 PM

I just wrote a long msg about how to check/replace needle and seat but my login timed out.God I hate that.
Go to Denniskirk.com and search part number 17-0531. That will fit your carb but check old one first. It doesn't take much for these to stick open. Look for boogers on needle or in seat and blow air through fuel inlet when diassembled. I can walk you throught it if need be.
Later.....
Vic

9C1 · 11-19-2012, 08:05 PM

Thanks guys - I should have some time later this week to get out there and mess with this. I appreciate the help and will let you know what I find.

**BC_Dan** · 11-19-2012, 10:07 PM

There's a good tutorial on how to disassemble and clean Mikuni round slides in the stickys in the How To part of the forum. It should give you everything you need to know.

93sportwithkids · 11-29-2012, 08:50 PM

The fuel level in your carburator should never get high enough to leak out around the bowl gasket. If you see that your needle and seat are either stuck open, or there is some trash preventing it from seating closed. Remove and replace your neele and seat, dennskirk has a good price on OEM Mikuni needles and seats. That carb is easy to rebuild, just be sure to clean your idle passage well. I would also recommend a new fuel filter since you have done this much, it will prevent fouling your work.