Walbro GRIEF=*%&**

[joe1267]

I just rebuilt the walbro on my wifes 400. It was dirty as hell and wouldn't hold idle. I purchased a real Walbro rebuild kit,took pictures, and followed the diagram in the technical section to a tee. Took my time cleaning it very carefully. All screens and orifices are clean. The metering arm is just about even with the body of the carb. The high needle is 3/4 turn out and the low speed is one turn out. I connected it to the sled, put the impulse line on, the fuel line to the bottom and the return on the right side nipple. It fired right away but stalled out almost immediately. I went back to pulling and noticed that a pretty strong drip of fuel is coming out of the mouth of the carb. Anyone have a clue what I am missing? I can't imagine that that much fuel should be coming out of the carb. This is my first Walbro rebuild, but not my first carb rebuild.

It is a gorgeous day and it doesn't seem like she will be riding today.

[400brian]

There shouldn't be any fuel coming out of the intake side of the carb.

The metering lever is critical . If you run a straight edge across the carb body, the metering lever should depress slightly as it goes over. I think we have something in the FAQs about this.

[joe1267]

Brian, the metering arm only depresses slightly when I put my straight edge across it. Stupid question, but the fuel line connects on the bottom of the carb and the return is on the right side if I am sitting on the sled looking at the carb, correct? The only other thing I was uncertain of was the metering diaphragm which has several metal circles on one side and only one in the center on the other. I currently have it so the single disc is facing the body of the carb. The diagram was not too clear on that one.


My JDX8 is running great. Hopefully we can get this one going as well.

[Matt]

I can never remember which way that plate goes either, but it sounds like you should try flipping it over.

[SpitfireKing]

The diagram I'm looking at shows it that way, disc to the top as you work your way up. I always just start from scratch when stuff like this happens....never know if something just got bumped during re-assembly

[400brian]

Brian, the metering arm only depresses slightly when I put my straight edge across it. Stupid question, but the fuel line connects on the bottom of the carb and the return is on the right side if I am sitting on the sled looking at the carb, correct? The only other thing I was uncertain of was the metering diaphragm which has several metal circles on one side and only one in the center on the other. I currently have it so the single disc is facing the body of the carb. The diagram was not too clear on that one.


My JDX8 is running great. Hopefully we can get this one going as well.

I believe you are describing the fuel line connections correctly. The supply line to the bottom center, return line to
fitting off-center bottom, and the impulse line goes to the fitting on the side of the carb.

Your description of the orientation of your metering diaphragm sounds right, but it has been a couple of years since I've been inside one, so I went and opened one up. This is what I found:

[joe1267]

Guys, I appreciate all of the input. Have the carb off and am going to go back thru it while watching the Viking's game today. Will keep you posted. Hopefully I just put something in the wrong order. Hope everyone has some good snow to ride on today. The drag races start in another two weeks here on out little lake. It is a mile long,pretty straight and the ice is so SMOOOOOOOOOOOOOOOTH, plus you hook up with the NYS snowmobile trails on either side.

JDX8 here I come!