1962 FD 18hp running rich and flooding

smeltjr

Seaman Apprentice
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Jan 13, 2004
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35
I picked this up for a 14 footer.
New parts on magneto all. Had most of them. Spark is good. Timing light when running between lines. Seems good.

Carb kit. In ultrasonic two rounds with tags thru all openings. New bulb connectors and line. Starts ok the carb needles do nothing. Bulb doesnt get hard. Looks like classic float needle. I got a new fuel pump. Carb is off.

Question is I thought if held carb upside down and blew thru the gas inlet it should hold pressure. It does. But what should it do if i blow thru upright? It still does not let anything through. Should it and is something blocked? Thoughts????

Plugs get
 

lindy46

Captain
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Nov 27, 2008
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3,886
With carb upright, the float is down and the needle valve is open - air should pass if you blow through the inlet. If not, the needle is stuck shut in the opening. However, you say the bulb doesn't get hard when you pump it - that indicates the needle valve is open or fuel is getting past the pump. It can't be doing both. Do you see fuel leaking?
 

Crosbyman

Vice Admiral
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Nov 5, 2006
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5,109
flooding means the inlet needle is not doing it's job or the float is not pushing it shut when the bowl is full of gas

just like a toilet bowl should shut the water off...... when full !
 

F_R

Supreme Mariner
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Jul 7, 2006
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28,195
Mud daubers in the vent will cause it. The ultrasonic should have taken care of it, but who knows?
 

oldboat1

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Apr 3, 2002
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9,612
If using a carb kit, use the new needle and wire clip supplied with it.

And always pee in the bowl, not the tank. Remember to put the seat down before leaving, and take out the garbage if that’s what you’ve been assigned.
 

smeltjr

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Jan 13, 2004
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35
Mais oui! I do admit that sometimes I have had to pee in the river.
If you look at some history I posted about this motor last spring.and put it up and walked away. I wanna use my boat this summer and fish.

Some history is that I got this on the cheap and it was pretty clean and had 95+ compression per cylinder. I had a full loaded magneto with new coils, condensers, points and wires from an old QD project. Swapped in the whole magneto/plate in with the new out with the old. Cleaned the points, set the points with an ohmmeter, flywheel on, spark good. Done with that.

Pulled the carb. Believe the kit was oem as I have a new float. Ultrasonic, tag through every orifice i could find, carb cleaner throughout, back in the cleaner for round two, sprayed out again. New welch cover, flloat, kit, packing washers, good to go. Dummy dropped the external glass filter so I have a fuel line direct with an inline filter to the carb fuel inlet.

New impeller. New J6C. Tank is a metal yamaha with yam connector at tank and OMC at motor connection, new fuel lines. 1.5 turns out on the low speed and 3/4 on the high. The bulb DID firm up at first. Ran rough but started just fine. I could keep it running but died at lowering throttle, then the bulb thing happened where it would not firm up. New bulb - same result. Turning that low speed needle almost all the way in had no effect. The plugs were extremely black, very wet and gas covered. I put it up, it went through the Chicago winter and I pulled the damn thing out.

My thoughts were it is way too rich so the needles wouldn't have any effect anyway if it is sucking gas. Maybe a pump diaphragm, they are cheap so I put one on.I read to turn the carb over and blow and it should hold air pressure with no leaks - took the carb off and that was good. Then did it with it right side up and also held pressure. Note the gap in when I ran the motor with it rich and pulling the carb off yesterday. I also re-ran through the magneto and checked every part and have 1/4"+ blue jump. I guess I will go through the carb again unless anyone has any other ideas. I do agree with lindy that it cannot be both ways. Is there anything else that can cause flooding/rich besides incomplete spark - that was good last year and reconfirmed. Fuel pump? Or carburetor that could be missing? Guess I will re-kit it or get new float needle and valve and put it back together and give it a shot. I only wanted to do this once.

If I continue to get fits I will just pull out the old pressure tankQD-20. I just think it is a bit underpowered for a 68" wide 14' tin boat that is rated for a 30hp motor.
 

F_R

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Jul 7, 2006
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Did you take my vent suggestion seriously? Or just write it off as being from a nut?
 

tomhath

Master Chief Petty Officer
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Dec 5, 2007
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814
It does sound like the float or float needle is sticking, sometimes open sometimes closed.
 

oldboat1

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Apr 3, 2002
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I'm not sure the Yammi connector will work properly in combination with the OMC. You could be getting some air. Think I would be tempted to go with an OMC version. Also might pull the in-line filter out of the system and see if you get improvement.

What fuel pump are you using? If using the square replacement pump, your rebuild might be the issue (kind of complicated little rascals). One of the cheap ones out there might be worth trying.

And there is always the reed valves — broken or missing leaf can give wonky conditions (unable to tune). If the idle needle adjustment has no effect, something is wrong -- and can't rule out mud daubers nests in carb vent.

(Might post a link to your earlier thread on this motor — haven’t checked, but might be some leads there.)
 

smeltjr

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Jan 13, 2004
Messages
35
I am not writing off anything.
The vent will be my first try here. I thought the thing was clean enough to eat off of but makes sense.
Not sure on the theromstat thing. Used a new/old one that I had with a new gasket. Would this cause rich condition and needles to be unresponsive?
Regarding the metal tank it has a yam connector attached to the metal 6 gal tank. It has a j/e connector at the motor. Not sure how that would affect anything as I did not think the motor cared about the tank as long as connections were good. I probably babbled about that one.
New needle and screw in chamber are possible and cheap and ensure passage did not collect crap with the vent over the winter.
Can someone school me on checking the reeds?? I can see in the intake somewhat but is there a sure way.
BTW the fuel pump is completely brand new one sierra/omc square one about $30. I am going to check the above and barrel this weekend. Thanks! Doing some work/work tonite.
 

Crosbyman

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Nov 5, 2006
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5,109
carbs don't "hold" the pressure upside down they just stop air going in the inlet because the float closes the inlet needle

right side up should let air flow in freely in the bowl........ if it does not the carb inlet is stuck shut

flooding is typical with an inlet needle not closing when the bowl fills with gas

forget the thermostat and reed s for now fix the carb till it meets the blow test



fix one thing at a time !! read lindy46 again
 

oldboat1

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Apr 3, 2002
Messages
9,612
The leaf valves are behind the intake manifold — leaf plate between two gaskets. Yours would have two circular leaf valves, visible for inspection if you remove the manifold (partly visible through the carb opening when the carb is removed). Problems are comparatively rare, but they can break.

(I misread your post about the fuel connectors — what you have should work fine.)
 
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