float bowl won't fill

[camanobass]

2006 T8 PXR no fuel in float bowl.
Nikki carb.
Motor wouldn't start after 2 months.
After thoroughly cleaning the carb It ran perfectly for 2 days. Now it won't start. Fuel bowl is empty. I disassembled and rechecked float needle and it manually shuts off and on OK when I blow through inlet, but when reassembly it still wont allow fuel into the bowl.
Incoming fuel to carb seems to be OK unless the pressure is too low to open the float needle valve or the float adjustment is not correct.
Can anyone help me find how to adjust the float and also how much fuel pump pressure should be? Or any other ideas. Tank, lines and filters are cleaned. Non ethanol fuel is new.
Thanks,
Frank

[panasonic]

If you take the fuel inlet line off the carb and pump the primer bulb, do you get fuel flow?

If the answer is yes to the above question, when you put the fuel hose back on the carb does the primer bulb pump up hard?

[TownsendsFJR1300]

With the carb off, pull the bowl.

The float should drop and the needle is now (SHOULD) off the seat opening it up for fuel. Verify, visually, the needle is dropping. Gravity makes the float drop (obviously)

You should be able to blow (simply by mouth) thru the fuel inlet and the float hanging down, Subsequently, with the float GENTLY pushed up, no air should float.

Some "needle to floats", have a slot for the needle or a small spring. Double check to make sure those are attached/installed correctly. (I don't anything on the parts parts fisch below). But ascertain the float drops and the needle opens.

As noted above prime the bulb, and check for hardness.

*You can also open the drain screw on the bowl to verify if you have fuel or not.

I don't have the spec's for your float setting but the float appears to NOT have an adjustable setting. In general, when closed, it sits even with the carb body. Shouldn't be pointing higher or lower...

Please report back..


http://www.boats.net/parts/search/Ya...TOR/parts.html


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[camanobass]

Hi,
Panasonic, with the fuel line off carb inlet I didn't check the bulb hardness but did crank the motor and fuel flows out the line. When line is attached the bulb does get hard but the bowl is empty. A quick spray of ether & it will fire off for a few seconds but still won't let fuel into the bowl.

Townsends, with the float bowl opened up and the float hanging down the needle drops and I can blow through the inlet and air flows fine. Then manually holding float up the air stops. Everything seems to be working fine with the float and needle valve. There is no spring involved with the needle valve, and the float is adjustable by bending the tabs that grab onto the bottom of the needle valve's plastic knob. When gravity pulls the float down those tabs, which are attached to the needle valve, pull the valve down, opening the fuel flow. But, after I reassemble and reinstall carb, the bowl won't fill and when I open the bowl drain there is no fuel.
My best theory: float adjustment tabs both pull the needle down but also push it back up, and that adjustment must be critical, I have just been adjusting by trial and error to get inflow open and closed to an approximate float movement up and down.

The float needle is the second one installed since the first one's little plastic pull down knob had broken off. That needle valve is aluminum with a soft rubber pointed cone shaped tip and the pull down plastic knob on the bottom end. I thought that rubber might stick sometimes and that's the reason the float actually pulls the needle down since it's so light weight to be able to fall on its own by gravity.

Thanks,

[TownsendsFJR1300]

I know its a PIA, but can you pull that carb, drain it, then do the "blow test" WITH THE BOWL ON, both upside down and right side up...

Also, maybe before the above, remove the drain screw in the bowl, prime the bulb and see if any fuel comes out. (as it should)..

I doubt it, but it almost seems like the float is hanging up on the bowl..

Also, re-reading the above post, there should be only ONE adjustment for the float level (in some much older non marine engines, I've seen a float DROP "STOP" setting(which yours likely does not have..

Can you post a close up pic of the float (where the needle touches) and the part that's adjustable?

[99yam40]

wrong needle, float, or maybe wrong float setting.
most likely the float is hitting something and binding up not allowing it to drop and open the needle and seat.

are you sure you have the correct parts in the carb?

[panasonic]

Hi,
Panasonic, with the fuel line off carb inlet I didn't check the bulb hardness but did crank the motor and fuel flows out the line. When line is attached the bulb does get hard but the bowl is empty. A quick spray of ether & it will fire off for a few seconds but still won't let fuel into the bowl.

Townsends, with the float bowl opened up and the float hanging down the needle drops and I can blow through the inlet and air flows fine. Then manually holding float up the air stops. Everything seems to be working fine with the float and needle valve. There is no spring involved with the needle valve, and the float is adjustable by bending the tabs that grab onto the bottom of the needle valve's plastic knob. When gravity pulls the float down those tabs, which are attached to the needle valve, pull the valve down, opening the fuel flow. But, after I reassemble and reinstall carb, the bowl won't fill and when I open the bowl drain there is no fuel.
My best theory: float adjustment tabs both pull the needle down but also push it back up, and that adjustment must be critical, I have just been adjusting by trial and error to get inflow open and closed to an approximate float movement up and down.

The float needle is the second one installed since the first one's little plastic pull down knob had broken off. That needle valve is aluminum with a soft rubber pointed cone shaped tip and the pull down plastic knob on the bottom end. I thought that rubber might stick sometimes and that's the reason the float actually pulls the needle down since it's so light weight to be able to fall on its own by gravity.

Thanks,

Thanks for answering each of our questions in order, makes things easier. this problem is a bit strange...most times the needle valve will not shut off and the engine runs rich and/or floods. But here we are...

I agree with Townsends reply. You will have to remove that carb again. It seems that the float is hanging up on the float bowl when you put it back on for some strange reason.

When you take the carb off again, give it a shake and you should HEAR that float bouncing up and down in the bowl. And as Townsend said try blowing in while the float bowl is still on and tipping the carb upside down and right side up and see if it is actually working when together.

As for the float adjustment, with the bowl off and the carb upside down, the bottom surface of the float should be parallel with the split line of the bowl and the main body of the carb. That would be a good place to start. I don't have a Service Manual so I cannot say for sure that is 100% correct. I am just going on what I have seen in the past on these small carbs.


See attached picture of Carb kit. It lists the same part number float as in your carb does it look the same as this one?

Please take a picture, if possible, of the carb with float bowl off...it would be a great help.

[camanobass]

Float valve is not opening for sure. With carb still installed and drain plug opened no fuel with bulb squeezing. I removed carb and blew through intake with float bowl still attached and air DID blow through but with some resistance. Turning carb upside down, so float simulated a full bowl, the valve did stop the air from my lungs. With the bowl off so the float can drop lower, air flow is not restricted, valve is opened fully. So this convinces me it's the adjustment of these float forked tangs that will pull the valve down earlier but also closes when bowl gets full. With the float removed needle does not drop by itself without a little shaking or removing it with tweezers. I think that is why the float's forked tangs also pull down on the valve, probably because of the soft rubber pointed needle doesn't release with just gravity.

Sorry but I can't get the pics to upload!

99yam40,
Yes parts are correct, and float is moving up and down very freely. I'm sure its the adjustment that I can't find any measurements or instructions on how to adjust it.

I'm going to keep trying trial and error adjustments a few more times then give up and take the carb to the Yamama dealer and see if they know how to adjust it.

Thanks for your ideas,
Frank

[TownsendsFJR1300]

The pic from Panasonic blown up helps a BUNCH looking at both the needle and float. Thanks Panasonic.

Quote: these float forked tangs that will pull the valve down earlier but also closes when bowl gets full" end quote. Incorrect (or I'm not understanding this), please read further...

Can we assume the "fork" part of the float is installed around the very thin/lower(while installed) end of the needle?

**That "fork" is to help pull the float down (should there be an issue sticking. Gravity should allow the needle to drop (and open normally-float dropping normally).

Obviously, the "flat" part of the float that touches the needle END is the flat level adjustment.

As noted, (without float spec's), the float is set generally good when the carb is upside down and the middle is parallel with the gasket surface.

IE, the needle should be set literally in-between the "fork" and the flat, metal part of the float. Make sure it's NOT binding..

Most of this may already be known, just verifying or bringing to your attention..

[camanobass]

Got it running and float bowl's filling properly. Yes, that pic of the rebuild kit is the right float. The float's 2 little forks pull the needle down to open and just below (as it sits installed) is a flat spot that pushes the needle up to close as the float rises. I bent the forks a bit closer to the flat spot closing the gap which then pulled the valve down as soon as the float started to drop. Before this adjustment the float would move down about a mm before the forks made contact to move the valve. I bet there's a dimension specified for the gap between the forks and the flat spot which could be easily measured before assembly. I have two of these floats and that gap was a little different between them. Also that plastic bottom end to the valve moves about a mm and has a internal spring pushing it downward. So as the rubber pointed end closes off the fuel that spring cushons the upward pressure from the float so as not to crush the rubber end too much.

The motor's been running perfectly now for over a half hour. That adjustment was the answer.
Thanks for all your diagnostic ideas,
Frank

[panasonic]

Glad to hear that. I am curious what you run that little engine on?

[TownsendsFJR1300]

Congrates!!!