js550 plus line

[bluegtate]

ok i just rebulit a 550 motor had the carb rebulit. as the book say i hooked up the fuel line and when trying to start it fuel is going down the plus line what do i do please help

[Technical Support]

I'm not sure what you mean 'as the book say'.

The bottom line to the carb is fuel in. The center is pulse, the top is fuel return. If your lines are connected correctly, something is very wrong inside the carb.

[poozine]

I know the person that posted the original thread on the pulse line for the 550. The ski has been a garage queen in my garage for about 5 months now.

The ski has a mikuni 44mm carb on it. We presently have the gasoline supply line connected to the nipple locate on the surface of the round body of the carb. The pulse line is connected to the nipple comming out of the right side of the round body. The return line is connected to the nipple located on the upper left side of the carb body. We have the Crymler manuel and we have all the fuel lines just as the diagram specifies. We have also replaced all the lines accept for the reserve and main supply lines to the fuel tap. The vent hose is not obstructed.

The last post mentioned bottom middle and top, can you specify a little more where those location are on the carb. i.e. side of round body of carb, flat surface of round body on carb, the actually cylinder body

The carb was recently rebuilt and sent to us directly from PJS in southern california. We had purschased the rebuilt carb because our old one was just really messed up. Then we found out the engine didnt have good compression. So we did a top end rebuild with a new/used bottom end that was in really good shape. We just slapped everything back together and now we are having the problem of the pulse line having fuel in it.

Is there suppose to be a line restricter located in-line on the return line? When we had another ski worked on by PJS they put a in-line restricter on the return line. Could that be causing any problem. When we took that old busted carb off the ski before we rebuilt the engine, we noticed that the previous people had done a similar job by filing the end of the nipple that comes out of the carb for the return line up with lead or some other material, and when it dried, he drilled a small hold out so it restricted the flow of gas coming out of the carb.

I know that was a lot to read, but that is all the I have found out so far.

[Technical Support]

OK, I think you're problem is that you are looking at pictures of a stock BN carb, where the fuel inlet is in the center, but you have installed an aftermarker SBN carb, which is completely different - and you have installed the lines incorrectly.

Watch this video to clear it up: http://www.sbtontheweb.com/ubb/ultim...pic/23/10.html

[poozine]

Hey that makes total sense. I haven't gone out there yet and tried it but it sounds like it will work. So if the it is a SBN carb, are all the jets in the same place as the ones in my Crymler manuel? And since it is the SBN carb, what are the settings I should start at? Especially the pop off pressure, how many turns should I have it out from seated? I don't have the gauge to measure the pop off presure so I have to do it just by turning the knob. Thanks again for every thing.

[Technical Support]

I don't know what you mean by turn the knob - pop-off has nothing to do with a knob. Read our carb articles, SBN rebuild guide, pop-off article and watch our carb videos - they will answer all your build questions and then some.

I have no idea where your jetting and needle setings should be, that's not the stock carb and I don't have experience with that combo, someone else might here.

[poozine]

Well I guess I didn't mean pop off pressure knob. I think I meant the atmospheric pressure knob. That is what the Cymler manuel calls it. On this carb I'm working with, it has three jets that you can turn. Non of them have labels either. Not even just a L or a H. If it helps at all there is one jet that I can turn located on the right hand side of the carb. There are two on the left hand side, one sitting above the other. I wish that carbs were easier than they are.

[Technical Support]

"atmospheric pressure knob" - I have no clue what that is.

Can you please send me pics of the carb and parts in question?

[poozine]

I took a look at the old carb that I took off the ski, and it is identical to the one that is presently on the ski. I did find that two of the three jets/knobs are labeled. The single jet/knob on the right had side does say L for LOW, and the top jet on the left side is labeled H for high. THe knob that is below the H knob does not have any label at all. I'm gonna get my buddy over here with his digital camera. Do you want me to send the pictures to the webmaster so that he can host them. I don't have any where that I can put pictures up and create links.

From my little experience with carbs, I do believe that I have the stock BN carb. I don't think that it is a SBN, those have square bodies don't they?

If it helps also, there are two holes for mounting bolts that go to the intake maifold. And there are four screw holes on top to hold on the spark arrestor. It is a one sided carburator. I took a look at that video you told me about with carb tuning with somone St. Louis. He had a double sided carb with a pump on one side and the other side to the regulator chamber. So let me know about those pictures. I can also email them if you like.

Another thing we are probably doing wrong is we have the clear gas lines on the ski. We have tie wraps around ever fitting to make sure there is no air leaking it. I know you aren't suppose to use that clear tubing, but it is all my local auto parts store has right now, and I can't make it to a Kawasaki dealer until next week.

[Technical Support]

I'm not aware of any 44mm BN carb, so that's why I presumed it's an SBN. hit my email button above my post.

[poozine]

It may not be a 44mm then. I'm not sure. 40 mm maybe. How would I be able to measure it?

I tried switching then lines acording to way that you posted earlier, and when I do that, it gets ride of all the gas in the pulse line, but then there is not a solid flow of gas coming from the supply line. Also no matter what combination I try, I cannot get the return to fill up solidly.


I drove over to my storage yard where I have a double carb 550 with mikuni carbs on it. I think these are 38mm carbs. I'm not sure. But anyways, I looked at all the line connections and they are indentical to the Cymler manuel and identiacal to the way that I had posted earlier. That ski runs so I know that the connections are correct.

The carbs that are on the double carb 550 look very similar to the one I am having all the trouble with. The only difference is the double carb ski's carburators have only two jet/knobs, not three like the my problems ski that I think is a 44 mm.


So if I absolutly know that I have the connections all correct, why do you still think that I am getting fuel in the pulse line? Also the ski wants to start when I have the lines in the setup I currently am using. It kinda start then dies, but when that pulse line fully fills up, then it won't turn over at all, just like the ski is getting flooded.

My buddy is comming by in about an hour to take the pictures I'll send them to you then,

[Technical Support]

Then you do indeed have a BN carb, and no, it's NOT 44mm. Measure the bore at the base to size it, but it really doesn't matter what size it is at this point. Connect the lines as your other ski, it only runs one way. Most likely something is not build correctly in the carb if you cannot get flow, and the needles are adjusted correctly. That model has three screws for mixture adjustment - idle, low and high. I don't know where yours need to be set, you can probably get it running at least with all at 1 turns out to start.

[poozine]

So that last screw is a idle mixture huh? So there is an idle mixture and an idle adjustment? Idle adjustment being on the throttle linkage itself?

I really hope there is nothing wrong with the carb. I really don't think that there would be. IT was rebuilt by a professional company. It was rebuilt by PJS Pacifc Jet Sports here in california. I would really hope that they know what they are doing. I have all the screws alteast a full turn out. So I would think that there should be some type of flow going through the carbs to fill the lines completley.

The supply and return lines should be pretty much full, correct?

[poozine]

By the way, thank you again for all your help. This is the most response I have ever gotten out of a fourm. Lighting fast responses too. Thanks

[Technical Support]

Correct on the screws.

If you remove the return line and blow through it, the lines and carb will be pressurized ready to go.