Keihin Carb

[etripp111]

Hello everyone.

I have a 1987 Yamaha Inviter 300. It has a Keihin butterfly carb. Last season I removed it form the sled and disassemble and cleaned it. The sled ran awesome after I did that, but this fall when I tried to start the sled it wouldn't start. Last season it kept flooding and wet fouling the plug. Its doing the same thing again. Could there be something else wrong?

Also I cannot find any info on this carb or if there is a rebuild kit available. Would I be wasting money replacing the float and needle valve? I just can't see what else could be wrong, I even removed the air box, thinking there was an obstruction keeping the carb from getting enough air......

Thanks

 

[Gorkon]

How do you have your enrichment plunger set? Sitting all the way on the bottom with no tension, they won't idle, too much and it gets too much gas. Also, I saw a similar problem on a 340 enticer where the breather hose off the top of the carb was hooked up to the tank vent!!! Silly but true! Just checking. G.

 

[etripp111]

I never thought to check that. How does that work? I thought that if I pulled the lever up that enriched the mix? So it seems if it was stuck it'd be stuck closed?

I'm not second guessing you, cause I don't know a lot about this stuff. How do I go about checking that? How do I adjust the plunger?

Thanks for you help.

 

[Gorkon]

The adjustment is in the two nuts and the threaded sleeve. I would disassemble and clean everything again first to make sure their is no garbage in there, you can be amazed what a guy sometimes finds AFTER cleaning!

If you put the plunger in the hole and adjust it until there is no tension on the choke lever. This means the plunger is sitting right on the bottom and no fuel will get through to the idle circuit. If you look at the carb you will see three little holes in the roof of the carb behind the butterfly, thats where its allowing fuel to go when you adjust the plunger up. I adjusted mine as it was running until it would idle.

I don't know the factory setting, but with a little trial and error you can find the sweet spot.

I don't even know what the main jet size is, but check that too, if you haven't owned it since new, you just never know, though from the sounds of things that doesn't sound like the problem.

You could conceivably have a float problem, I never had to mess with mine. If you eliminate all else and you still have problem, maybe take it to a good dealer mechanic and have him go through it. Good luck. G.