96 SPX revving high , bogging down when throttled

[KennyBooth]

Hi, i recently installed two freshly rebuilt carburetors on my ski, the problem i seem to be having is upon starting my ski and i use the throttle, it'll bog right down, then on top of that my RPMs sky rocket almost as if it is running away but i can still kill it with the off button. I am currently completely lost on what to do from here. I'm pretty new to this so anything helps, thanks.

 

[SIMPLEARKANSAN]

Did you use new carb base gaskets?

 

[mikidymac]

Yes first check the base gaskets then verify your throttle closes all the way. On some it’s possible to put the throttle cable end in the wrong hole and it can hold the throttle open. Also make sure you have slack in the throttle, you should have 2mm of free play at the handlebar throttle lever.

 

[KennyBooth]

Did you use new carb base gaskets?

Yes i am using the new gaskets

 

[KennyBooth]

Yes first check the base gaskets then verify your throttle closes all the way. On some it’s possible to put the throttle cable end in the wrong hole and it can hold the throttle open. Also make sure you have slack in the throttle, you should have 2mm of free play at the handlebar throttle lever.

I hAve a video of what exactly is happening , if there’s anyway I could send it or post it here to help out more

 

[SIMPLEARKANSAN]

Upload to YouTube and share link in your post.

 

[KennyBooth]

if you look at when my friends using the throttle , it wouldn’t allow us to throttle it any more before bogging down also when it pegged out the RPMs that was the only time it did it that harsh but prior to that the rpms would slowly shoot up without us using the throttle

 

[KyleW2]

Does it always rev up right after releasing the throttle, or if you let it idle (without touching throttle) will it rev up also?

You said the carbs were recently rebuilt - were they rebuilt with genuine Mikuni parts?

 

[KennyBooth]

Does it always rev up right after releasing the throttle, or if you let it idle (without touching throttle) will it rev up also?

You said the carbs were recently rebuilt - were they rebuilt with genuine Mikuni parts?

It would sometimes rev up without touching the throttle , also they were rebuild with genuine parts, I took off both sides to check the fuel jets but I haven’t gotten to the fuel pump side . A good majority of people have told me that it sounds like I have an air leak somewhere in my system but Like I said I’m pretty lost right now

 

[mikidymac]

Wait, how did you rebuild them but not check the fuel pump side?

Also check your throttle cable adjustment and make sure the throttle butterflies aren’t being held open.

 

[KennyBooth]

Wait, how did you rebuild them but not check the fuel pump side?

Also check your throttle cable adjustment and make sure the throttle butterflies aren’t being held open.

I had bought them rebuilt, from a company off of eBay who had good feedback and what not and i mean, I’m going over the carbs again to double check everything and I looked at the side w the jets just not the fuel pump side yet , and everything with the throttle is good. I ended up finding water bubbles in the carburetor that doesn’t have the fuel pump . Could that be my issue?

 

[mikidymac]

Yes, water is too viscous to pass through the jets and will actually plug them.

I would be suspect of any “rebuilt” carbs from eBay.

 

[KennyBooth]

Yes, water is too viscous to pass through the jets and will actually plug them.

I would be suspect of any “rebuilt” carbs from eBay.

I also agree but I was doing what I could with the money I have right now, so after cleaning the carbs the throttle no longer bogs down When you use it but, it will still shoot up in RPMs almost as if it’s not getting gas or there could be an air leak?

 

[mikidymac]

If the rpm’s climb up to full throttle by itself and runs away then it’s an air leak.

If the rpm’s go up with throttle and won’t come back to idle it’s usually lean.

 

[KennyBooth]

If the rpm’s climb up to full throttle by itself and runs away then it’s an air leak.

If the rpm’s go up with throttle and won’t come back to idle it’s usually lean.

So here’s what’s exactly happening. When I start it up and I go to throttle it will bog down , but when I choke it it will throttle up fine, and after I take it off choke it will continue to run fine. After I turn the ski off I have to keep repeating this process

 

[KennyBooth]

UPDATE: I took it into the water with it all back together to see if anything changes and it did , at first it ran a little rough but soon enough it was riding great