Kawasaki FD620D running poorly. Help?!

[JohnF]

Did you snip all of the narrow portion of that anti-fire solenoid off? I had problems that sounded like yours that went away when the anti-fire solenoid went away. What is the condition of your fuel line? If it is coming apart inside it will plug up your main jet (just like an anti-fire solenoid ).

When it is dead is there fuel in the bowl? You can take the lid off and peek. If so, I suspect something is plugging the main jet. If not, then float, float valve, fuel line, pump, filter, tank...

GEEZ. I read your post but I didn't READ your post... You already suspect that there isn't fuel in the bowl.
A float that doesn't float will run the engine really rich and/or spill fuel out the vent hole in the top of the carburetor.
Check the float valve. There is a picture in the service manual. Usually they wear out and stop stopping fuel so act just like a float that doesn't float.
So, float that sticks up or valve that sticks closed or plugged fuel line.

I think you are on the right track.

Not seeing fuel dump when you twist the throttle could be a plugged immersion tube.
- or a too low float level.

I keep editing - I hope you are getting these.

[gimmegreens336]

I see what you're saying.

I want to take some pictures when I get home of the carb before installing. I've dropped, emptied and cleaned the tank. Replaced the fuel line, fuel filter and fuel pump. Getting good fuel flow up to the carb. What would the symptoms be if the float were getting stuck at the top?

I need a better understanding of the flow of fuel through the carb. It enters from the fuel line and has to pass the float needle immediately? If the float were to stick at the top would it prevent all fuel from entering?

I am going to go back a few pages and read your explanation of the carb again. I read, re-read and re-re-read when you first posted but a lot of it was spanish to me. I am soaking this information in though please keep it coming!




EDIT: Disregard this post

[gimmegreens336]

If the float was stuck closed then it wouldn't run at all. Yours is running at low idle.
If the float didn't open enough to allow a fuel rate enough for high idle then it would probably reach high idle and then surge. Unless it was really bad, then it would die.
The float level affects the "accelerator pump" function of the carburetor. This functions is accomplished via an immersion tube (huh, the parts blowup in the manual above calls it an Emarsion Tube???) that sits in a reservoir. When call for, the fuel is sucked out of this reservoir. As the level drops it un-ports air holes in the tube effectively increasing air. What is trying to happen here is when you open the throttle the air flow can accelerate faster than the fuel which is heavier so the carb meters a bunch more fuel at this change over. The important part (sigh) is that the reservoir level is the same as the float level. If the level is too low, then the air/fuel gets too lean and the engine dies. If this is the case, you should be able to creep slowly to high idle.

As a side note, the main jet is in the bottom of the float bowl. If the float is set too low the engine will run fine on the level but die when the jet un-ports. Probably pointed downhill or port side high. That's really a function of the float bowl geometry in the design but a too low float adjustment screws that up.

I'm still thinking bypass holes are plugged. Second guess is fuel pump or float valve not allowing enough fuel flow through.

And for draining I usually unplug the fuel pump and let the engine run it mostly dry.

Here we go, save the back peddling.

Edit: Is the carb the same for all these Conquests with FD620D? If so, what is the model? I wanna see where all the fuel travels through it... Or you could just explain it all :-D

Re-Edit: What do you mean, when the main jet un-ports?

Thanks!

[gimmegreens336]

I hope you're not typing while I'm typing this.

A perfect explanation of the flow is in the service manual. I read this explanation a million times when I first started this thread but my understanding is much better now. I understand everything that needs to be un-obstructed. (I think.. lol)

Let me clean this one more time and re-install her and see what happens.

Will check back.

[JohnF]

Yeah, all FD620Ds and FD661Ds have the same carburetor. Uh, model... That's actually in my other post, hold on... wait, I'll link the file here too <going advanced>:

FD620D-FD661D jetting.jpg

Go and download the service manual.
It's a terrible picture but page 2-8 describes how the carburetor works.

The main jet is at the bottom of the fuel bowl and is supposed to always be under the fuel level in the bowl. what I meant by un-porting here was when the jet moves above the fuel level and air start moving through it.

[EDIT] Oh, too late, I was typing...

[gimmegreens336]

Haha! I see that!

I have def not done this... not sure I understand either. Does this have anything to do with my issues?

[JohnF]

Nope, you're not to this yet. Once it's running well.

Stick with your instinct that you aren't getting enough fuel in the bowl. Might be that all of your parts are okay but you have a really bad adjusted float.
Review 2-13.

[gimmegreens336]

Nope, you're not to this yet. Once it's running well.

10 4!

[JohnF]

The picture there isn't very good. If you've never seen a float and needle before then that thing is't helping you.

Hold yours upside down like in the picture and take a pic and post it. What I want to see is if you have the tab between the valve and its little keeper wire. If you have it on top of the wire then you effectively have your fuel shut off.

[gimmegreens336]

I'm headed home shortly. I will have a pic by tomorrow.



There is a little wire, maybe the "keeper wire" that "clips" (fits in a groove) on the needle. The wire has a little rectangle that slides into the tab on the float assembly. The needle is connected to a tab on the float assembly by the little wire thing.

I adjusted the tab according to the directions above.

[JohnF]

Well, that sounds right. But you gotta admit, that's a terrible picture.

[sparkola]

If you got the dough, I would buy a new carb. You can always get a rebuild kit for your old one and keep it as a spare for when the new one clogs up. I'm tellin ya you gotta sonicly clean that thing for like an hour. It will clear those main jet passages like you wouldn't believe.

[Slimpickin]

Check the needle and seat. I've had two 620's act the same as yours and the intake above the seat was plugged or partialy plugged. Use an air hose to blow back where the needle seats. Carefull using anything metal to unplug it cause you will damage the seat. Blow back and forth both ways. Not a very big hole coming into the seat so it could easily be plugged. I changed lines and filters on these machines and a little rubber or dirt plugged the seat.

[gimmegreens336]

Well, that sounds right. But you gotta admit, that's a terrible picture.

Yeah the pics in the manuals are awful. Makes it harder on someone trying to learn like myself!

If you got the dough, I would buy a new carb. You can always get a rebuild kit for your old one and keep it as a spare for when the new one clogs up. I'm tellin ya you gotta sonicly clean that thing for like an hour. It will clear those main jet passages like you wouldn't believe.

I'm not sure what the sonic cleaner you're talking about is, but, my wife is a dental hygienist and I used her water pick and some scalers. lol.. I am going to buy a new carb for sure, I'll use the current for parts.

Check the needle and seat. I've had two 620's act the same as yours and the intake above the seat was plugged or partialy plugged. Use an air hose to blow back where the needle seats. Carefull using anything metal to unplug it cause you will damage the seat. Blow back and forth both ways. Not a very big hole coming into the seat so it could easily be plugged. I changed lines and filters on these machines and a little rubber or dirt plugged the seat.

I was so embarrassed last night to admit I neglected that particular hole while cleaning. The bottom half of the carb got the deep cleaning. There wasn't a speck of grime on the bottom half. BUT - I neglected to clean the very FIRST hole fuel passes through. Fuel cannot even get to the other jets or bowl or anything without first passing that hole. I'm not sure if she's fully fixed (because it was 3am and I was too tired to take a drive) but she cranks up and revs and operates correctly in neutral after cleaning that hole. I also did a float adjustment but I'm almost positive that hole was clogged.



Two major issues fixed: cleaned the hole at the fuel inlet on the carb and bent the float, it was slightly off center. I don't believe the flloat had free flow in the narrow channel in the bowl. I think with it being off-center it was preventing it from rising up and down like it's supposed to.


Anyway, I'm going to try and ride this evening to see what happens.


This is how I interpreted the float adjustment:

[plott hound]

make sure the main jet is clear bud.its the one behind the fuel shut off solenoid.solenoid must be removed so you can extract it.turns out with a flat screw driver.