2005 Johnson 15 hp 2 stroke carb float sticking open

[gpgeerd]

Hi. Hoping someone can help. I have a 2005 Johnson 15 hp 2 stroke. A few years ago I noticed gas coming out of carb overflow. Dissembled carb and determined float was swollen with gas. So I bought a full carb kit and installed it. I used Johnson/Evinrude brand name parts. Adjusted float with a little over 1 inch drop when open and even with carb body when closed per the shop manual. I previously ran 10% ethanol fuel and now only run recreational fuel. Stabilized after each trip. When I rebuilt the carb it looked spotless inside except for the swollen float. Since then I've been having intermittent problems with float sticking open and gas coming out carb overflow. Sometimes I can run for several days and then it just sticks. I even went so far as to get an additional carb kit and still same issue. Also checked fuel pump filter to see if any debris might be in it and decided to just rebuild the fuel pump also. I also checked hoses inside motor for breakdown of rubber and they look fine even inside. I took the carb and hoses to a marine mechanic and they said it looked fine to them. Anyone having problems with newer carb kits? I checked for burrs on the metal part of the float also to see if was catching and did a little cleanup of some sharp edges on the tang. Could the float be getting stuck on the bottom of the bowl as the amount of drop in the float would allow it to hit the bottom? Noticed in the bowl picture below there is a groove in the bottom of the float-could it catch on that when fully open? When I assemble the carb dry and turn it upside down the float seems to flow freely. I noticed the new float rides a little looser on the pin then the old. The gas tank and line running to the motor are fine as a spare motor runs perfect. Any help is appreciated as I'm running out of ideas. Thanks for your help! A few pictures enclosed. I've rebuilt a lot of carbs over the years and haven't seen anything like this before.

 

[gpgeerd]

I have an update after studying further and doing some measurements and more tests. I believe the root-cause is the float is getting binded intermittently in the float bowl when the float drops. The float bowl has smaller internal dimensions than the carb body (1 7/8" versus 2"). I see the newer johnson/evinrude floats are manufactured with fairly loose tolerances compared with the older ones also. The result of the new floats are they are looser on the pin which allows more slop in movement and can rub on the side of the bowl when going up and down as the float fills and empties. I have an older float I tested and it rides much tighter on the pin and has very slop side-to-side. I think I will need to try to squeeze the hooks of the new float tighter to eliminate the problem. I see other people that have had this problem after putting in new floats also. They went back to their old float and no problems. I think it will all be dependent on what carb you have whether you have the problem or not because of tolerances inside the float bowl. Not sure if someone else makes a johnson/evinrude float.

 

[puffitu]

Not an expert on this but did a few rebuilds in my day. From past experiences I’ve always adhered to not let the float come in contact with the carb body upon drop. And buy only omc if you can ! There’s a lot of cheap crap out there these days

 

[LindenLongRods]

Might be unrelated but float pin is triangular not round. Maybe hanging up??

 

[puffitu]

Shouldn’t hang up if installed correctly

 

[Crosbyman]

make certain any new gasket does not extend into the float movement zone inside the carb body... trim it if need be

 

[Sea Rider]

If all the mentioned carb parts are working spotless, seems the carb has repetitive needle sticking issues. Inspect with a flashlight the needle's seat interior, if severely gunk, dirty, crappy that seat needs an urgent micropolish to a smooth shinny condition. Roll tight a cotton piece on top of a wooden stick as seen, dampen it in water, roll it tight again, apply toothpaste, insert the stick into the valve and roll the swab with slight down pressure in repetitive circular motion it was rolled to.​

Repeat the procedure installing a new cotton on the stick till comes out white clean. That needle won't never stick again if that was the carb's problem. That carb will benefit to be run fuel dry after use or prolongue storage...​

Happy Boating

 

[gpgeerd]

I determined the issue. The float bowl gasket material was slightly protruding into the float bowl. I trimmed no more than 1/16 inch around the perimeter of the gasket and ran for 4 days of fishing without an issue. Why would a brand new OMC carb kit not fit correctly? Strange.

 

[Roberthill]

make certain any new gasket does not extend into the float movement zone inside the carb body... trim it if need be

Least time I put a kit in my carburetor had to trim gasket it was hitting the float causing it to hang up.

 

[oldboat1]

Is the small wire clip correctly hooked to the needle and the float arm (just slips around the arm, and the loop hooks the indentation on top of the newer needles -- that also have a black neoprene tip susceptible to sticking.)