650/X-2 CDK ii carb troubles... I think

[mase911j]

Hi all. I need some help.. badly!!! I got an older x2 (I think a 90.5 seeing how it has the direct steer system) for free. It has a westcoast waterbox (I think), a tunable pipe, oil injection delete, CDK ii 42mm carb and aftermarket intake manifold. The ski was put up about 10 years ago but everything was drained properly at that time. Now it won't start.

After new plugs, gas, fuel lines, cooling lines, etc... It turns over like a champ and has plenty of spark and compression. However, I cannot get it running. I just rebuilt the carb with a new Fuel Dynamic kit. I didn't touch the hi or low screws or the ree ds at all, but replaced everything else. I was left with a single o ring, one main seal and a small flapper valve (I am guessing this because this kit was for multiple carb versions).

This was my first carb rebuild and replaced everything as I found it so I was surprised to not see gas dumping down the carb throat after cleaning it all out. I tried to hold a pice of paper on the fuel inlet (the lower one on the carb) but I wasn't able to see if it was sucking or not. Also, I never saw any gas go down the throat or come out of the brass rod that goes across the carb throat area.

Could this carb be trashed? Do I need to do something with the hi and lo screws? Could the reeds be trashed and therefore it isn't creating enough vacuum to pump the gas?

The pics of the carb are attached.. any help would be appreciated!!!!

 

[kevbo]

Prime the carb by sucking on the return line. They don't pump very well when dry.

 

[mase911j]

Kevbo,

Thanks for the info. I tried sucking on the return line but never got anything... it was always hard and never released any pressure it seems. I pumped the gas and that didn't do anything either. Do you have any other suggestions?

I know this thing runs since it fires up with starter fluid.. but I hate doing that. However, the several times that I tried to get the carb to self-prime by cranking it over for 10 second-bursts I still never saw any fuel being sprayed into the throat by the carb.

Thanks for the help!

 

[7fiddy]

What about sucking on the fuel inlet to get gas to the carb ? Or try and pressurize the gas tank ? Or maybe hold your hand over the carb crank it see if it will pull fuel to the carb .

 

[mase911j]

Yes I have sucked it to the carb through the fuel line, but Ill try covering the carb and see what that does... Im not sure how I can pressurize the tank... I guess I try to blow into the return hose while cranking it over...

Thanks and Ill let you know in a few hours!!!

 

[7fiddy]

Yeah holding a hand over is choking it as if it had a choke . You should be able to pressurize from the vent on the gas tank .

 

[mase911j]

ok update... I tried to "choke" the carb.. it sounded like it was trying to start moreso than before but it never kicked fully over... then I pulled the return fuel line off the carb to see what would happen when I cranked it... fuel came out.. so Im guessing the pump works just fine but no fuel is getting to the carb throat.

So what now... correct me if Im wrong but there should be fuel coming out the bass bar in the middle of the carb's throat, right? Was i suppose to do something with the hi and lo screws when I rebuilt the carb? Does anyone know a good starting point as far as re-dialing them back in? Like how many turns from fully closed (to the right)?

Thanks!

 

[mase911j]

also, I wasn't able to pressurize the tank because my fuel line cap has a crack and I can't get a complete airtight seal... the ski also has an internal fill, but uses the fuel line cap as the fill port and the fuel on/off/res valve was removed. so I only have 2 lines going into the tank... the to-carb line and the return line. the rest are capped off... and I fill it at that cap as mentioned... does any of this matter?

 

[7fiddy]

Yeah fuel should be coming out of that brass . Getting a little more into what I know but if the tank can't keep pressure I believe that would cause a issue . These are just things I've tried when I've had problems . Now the high low screws I don't know about . Now if it has no vent then the tank will want to shrink in on itself open do you have a vent breather tube lets air in but not out a check valve and try and choke . Since you're sucking on the lines you said it was hard maybe that's why you suck on the line and it starts to suck the tank in makes it hard . Remember I am not an expert just trying to help .

 

[mase911j]

Yeah I hear you and appreciate the help!!!

 

[7fiddy]

Let me know what happens !

 

[Pro-pulsion]

Sounds to me it is a fuel line issue. If the fuel pickup in the bottom of the tank is not flowing then that'll do it. The carb itself looks to be in quite good condition and I noticed is a Sudco Racing modified carb. They were a really decent carb and yours looks to be very clean. Another easy area to check is the pulse line from the crankcase. Check it to make sure it is not cut or dry rot cracked, or on the wrong spigot on the carb. There should be arrows showing the fuel flow and a ~ to signify pulse hose location. Also, use mixed 2-stroke fuel to do prime starting, not starting fluid. Starting fluid has no lubricating properties and is meant for diesel engines what are basically fueled by stove oil, so they need more non-lubricated highly combustible alcohol or either based chemicals to help them start in cold weather.

 

[Tyler Zane]

Does it have a petcock?

 

[mase911j]

No there is no petcock, just straight lines to and from the carb... I checked the pulse line and its in good condition too... I am all out of ideas besides starting to mess with the idea mixture screw and high speed screws, and possibly a lighter spring in the regulator chamber area of the carb (although I thought I read the spring pressure shouldn't matter since Im running a single carb). I do need to pull the idea mixture screw and high speed screw anyways as I missed that during my carb rebuild...

Im losing my mind with this project! haha...

 

[Tyler Zane]

Pulling those screws is an important part of cleaning. I always spray brake clean and compressed air threw all the circuits.

Ive kicked myself in the ass so many times for not thoroughly doing something right the first time. I'd go threw the carb again.

Just a side note: You mentioned you used starter fluid... Please do yourself a favor and just use some premixed fuel. I just suck some up a syringe and squirt it down the carb/carbs.

 

[mase911j]

tzane, Thanks for the info and will do!!

So I pulled the Hi and Low (Idle mixture screw) screws out, cleaned them and reinstalled... I put both screws in all the way and tried to fire it up... it did fire up and stay running with the throttle wide open but dies when I tried to idle it... I then tried to back out the low screw to set the idle by 1/2 turn increments up to two full turns out and it still didn't start without any throttle. I suppose Ill keep working with the low screw until I can get it started/idling fine. Could this just be how it is since there is no choke on this carb?

What I don't understand is how it runs wide open fine with the Hi screw all the way in... Also, the Idle speed screw doesn't touch anything so I don't get how it sets the idle. I thought it usually contacted the back of the throttle plate located on the backside of where the throttle cable attaches to the carb.

Any thoughts on any of this?

Below is what I found from keihin that tells you how to set a carb up, but Im not an expert and don't know if I did everything correctly...

http://www.keihin-na.com/assets/1/7/cdk_jetting.pdf

Either way Im super pumped to get it running!!!

Thanks all.

 

[Tyler Zane]

I still think you may be neglecting to clean the carb properly. You cant just pull out the screws and clean them. You must full disassemble and spray threw all circuits., physically watching fluid spraying into the carb throat. The idle circit is the smallest and on a carb that been sitting for 10 years its likely going to need to be blow out a few times. Once you are certain its all clean and clean, blow it out with compressed air and reassemble.

With all that being said, dont get tunnel vision. You said it has plenty of spark and compression... did you actually check compression with a gauge? How did you check spark? I generally leave my spark gap tester to 7/16" If it can jump that its a good strong spark.

 

[badvinny]

Looks to me like you inverted the throttle linkage on the butterfly shaft when you reassembled, that is why the Idle screw is not touching the stopper. Flip it back over and give it some idle and it should start.

 

[Tyler Zane]

I did some looking around and found some diagrams of throttle linkages and the direction it should pull from. Its about half way down the page.

http://www.keihin-na.com/aftermarket/cdkii/

 

[mase911j]

Thanks guys.. I didn't take the throttle linkage off when I rebuilt it, but Ill play with it to see if I can get it working when flipped. This might have been the case originally since there are some wear marks on the butterfly rod nut. While Ill at it Ill spray out the idle and high speed circuits to see what happens.

Also I don't have a spark gap tester or a compression gauge... i just can't turn it over by hand, so i think it has good compression, and when I pull the plugs and turn it over, I get spark when I ground out the metal on the spark plug.

Attached are the leftover parts after the carb rebuild... did I overlook something?