Normal for carbs to leak when primed?

777funk

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When my Force 125 is primed, I notice drips of gas on the outside of the carbs coming from above the bowls. Is this normal? I also notice it when running trimmed.
 

Jiggz

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Oct 23, 2009
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When priming, normally there would be no leaks from the overflow/vent hole (located just above the bowl) assuming the float and needle valve in conjunction with the needle seat are sealing properly. Unless, you squeezed too much then you will overcome the inlet needle valve and fuel will leak out of the overflow/vent hole. If you are not squeezing too hard or the primer bulb doesn't even get firm enough to indicate the bowls are full, then it means your inlet needle valve is NOT sealing properly either because of worn out o-ring or improperly set float.
 

Frank Acampora

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The needle tip or seat, depending upon whether or not you have rubber tipped needles, are leaking. Since it happens while running and since the fuel pump can not generate enough pressure to force open an inlet needle it becomes clear that a carb rebuild is needed. At high speeds, the engine can use the excess fuel without much harm, but tell us: Does the engine run very rough at low to medium speeds?
 

gm280

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Jun 26, 2011
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I concur with the above comments on your carb. Time to clean and install a carb kit with new needle and seat and make certain the float level is set properly as well... Priming the fuel bulb shouldn't have fuel coming out of the carb... JMHO!
 

777funk

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Jan 12, 2015
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It's pretty rough in medium speed settings Frank.

I tested the float needle valve by connecting a hose and trying to blow into the carb's fuel inlets with the float held closed by hand and I couldn't blow past the float needle.

Can these floats develop leaks where they become 'sinks' instead of floats (i.e. fill with gas and won't stay up)? I wonder how well they're working. I know some floats can leak after time and wear.
 
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gm280

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It's pretty rough in medium speed settings Frank.

Can these floats develop leaks where they become 'sinks' instead of floats (i.e. fill with gas and won't stay up)? I wonder how well they're working. I know some floats can leak after time and wear.

To answer your question about the floats becoming sinkers...ABSOLUTELY they can. I know of three types of float material (probably tons more) and the plastic type can get a crack in them and fill up with fuel or partially fill up and make things not work properly. But you can usually shake them and tell. Also brass floats can do the same. But you can usually drill a hole in the brass floats and drain them and solder over the small hole to make them work again or just buy a new one. I also had a cork float get saturated and not work. So I just bought a new one and installed it. So you do have to check them over and see if they are good or not... JMHO!
 

jerryjerry05

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There can be some fuel leaking from the carbs.
The reeds can be bad and allow some blow back through the carb.
Yesterday I was finishing up a de-carb on a 225 Johnson.
Running with the cover off and was noticing fuel coming back through the carb.
Just a bit.
That's why they put a fuel recirc system on these outboards.
If it's a small amount I wouldn't worry. A bunch? Take carbs off and inspect the reeds.
Inspect the needle. It needs a smooth taper and any grooves will be trouble.
The 125 came with metal floats and they can leak.
There is a plastic replacement but it is the worst thing I've seen. Garbage!!
 
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